diff --git a/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_definitions.py b/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_definitions.py
index ef76270c..67043b85 100644
--- a/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_definitions.py
+++ b/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_definitions.py
@@ -165,7 +165,6 @@ class CorrelationProperty:
         self.name = name                            # This is the property name
         self.retrieval_expression = retrieval_expression  # This is how it's generated
         self.correlation_keys = correlation_keys    # These are the keys it's used by
-        self.expected_value = expected_value        # This is the (optional) expected value
 
 class MessageEventDefinition(NamedEventDefinition):
     """The default message event."""
@@ -206,34 +205,23 @@ class MessageEventDefinition(NamedEventDefinition):
         if payload is not None:
             my_task.set_data(**payload)
 
-    def get_correlation_keys(self, task, payload):
+    def get_correlations(self, task, payload):
         correlation_keys = {}
         for property in self.correlation_properties:
             for key in property.correlation_keys:
                 if key not in correlation_keys:
                     correlation_keys[key] = {}
-                correlation_keys[key][property.name] = task.workflow.script_engine._evaluate(property.expression, payload)
+                try:
+                    correlation_keys[key][property.name] = task.workflow.script_engine._evaluate(property.retrieval_expression, payload)
+                except WorkflowException as we:
+                    we.add_note(
+                        f"Failed to evaluate correlation property '{property.name}'"
+                        f" invalid expression '{property.retrieval_expression}'")
+                    we.task_spec = task.task_spec
+                    raise we
         return correlation_keys
 
-    def get_correlations(self, task, payload):
-        correlations = {}
-        for property in self.correlation_properties:
-            try:
-                correlations[property.name] = task.workflow.script_engine._evaluate(property.retrieval_expression, payload)
-            except WorkflowException as we:
-                we.add_note(f"Failed to evaluate correlation property '{property.name}'"
-                             f" invalid expression '{property.retrieval_expression}'")
-                we.task_spec = task.task_spec
-                raise we
-        return correlations
 
-    def get_awaiting_correlations(self, task):
-        for prop in self.correlation_properties:
-            if prop.name in task.workflow.correlations:
-                prop.expected_value = task.workflow.correlations.get(prop.name)
-            else:
-                prop.expected_value = None
-        return self.correlation_properties
 
 class NoneEventDefinition(EventDefinition):
     """
diff --git a/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_types.py b/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_types.py
index 846c6031..e1a01853 100644
--- a/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_types.py
+++ b/SpiffWorkflow/SpiffWorkflow/bpmn/specs/events/event_types.py
@@ -36,7 +36,7 @@ class CatchingEvent(Simple, BpmnSpecMixin):
 
     def catches(self, my_task, event_definition, correlations=None):
         if self.event_definition == event_definition:
-            return all([ str(correlations.get(key)) == str(my_task.workflow.correlations.get(key)) for key in correlations ])
+            return all([correlations.get(key) == my_task.workflow.correlations.get(key) for key in correlations ])
         else:
             return False
 
diff --git a/SpiffWorkflow/SpiffWorkflow/bpmn/workflow.py b/SpiffWorkflow/SpiffWorkflow/bpmn/workflow.py
index e6a41441..3f693981 100644
--- a/SpiffWorkflow/SpiffWorkflow/bpmn/workflow.py
+++ b/SpiffWorkflow/SpiffWorkflow/bpmn/workflow.py
@@ -179,8 +179,7 @@ class BpmnWorkflow(Workflow):
             if isinstance(event_definition, TimerEventDefinition):
                 value = event_definition.timer_value(task)
             elif isinstance(event_definition, MessageEventDefinition):
-                value = event_definition.get_awaiting_correlations(task)
-
+                value = event_definition.correlation_properties
             events.append({
                 'event_type': event_definition.event_type,
                 'name': event_definition.name if isinstance(event_definition, NamedEventDefinition) else None,
diff --git a/SpiffWorkflow/tests/SpiffWorkflow/bpmn/CollaborationTest.py b/SpiffWorkflow/tests/SpiffWorkflow/bpmn/CollaborationTest.py
index d2e27307..77e54726 100644
--- a/SpiffWorkflow/tests/SpiffWorkflow/bpmn/CollaborationTest.py
+++ b/SpiffWorkflow/tests/SpiffWorkflow/bpmn/CollaborationTest.py
@@ -56,7 +56,6 @@ class CollaborationTest(BpmnWorkflowTestCase):
         self.assertEqual(1, len(events))
         self.assertEqual("Message", events[0]['event_type'])
         self.assertEqual("Love Letter Response", events[0]['name'])
-        self.assertEqual('Peggy', events[0]['value'][0].expected_value)
         self.assertEqual(['lover'], events[0]['value'][0].correlation_keys)
         self.assertEqual('from_name', events[0]['value'][0].retrieval_expression)
         self.assertEqual('lover_name', events[0]['value'][0].name)
diff --git a/spiffworkflow-backend/migrations/versions/4d47598d7181_.py b/spiffworkflow-backend/migrations/versions/4d47598d7181_.py
deleted file mode 100644
index 721decab..00000000
--- a/spiffworkflow-backend/migrations/versions/4d47598d7181_.py
+++ /dev/null
@@ -1,35 +0,0 @@
-"""empty message
-
-Revision ID: 4d47598d7181
-Revises: 4ab08bf12666
-Create Date: 2023-02-23 16:12:11.603900
-
-"""
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision = '4d47598d7181'
-down_revision = '4ab08bf12666'
-branch_labels = None
-depends_on = None
-
-
-def upgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.create_table('correlation_property_cache',
-    sa.Column('id', sa.Integer(), nullable=False),
-    sa.Column('name', sa.String(length=50), nullable=False),
-    sa.Column('message_name', sa.String(length=50), nullable=False),
-    sa.Column('process_model_id', sa.String(length=255), nullable=False),
-    sa.Column('retrieval_expression', sa.String(length=255), nullable=True),
-    sa.PrimaryKeyConstraint('id')
-    )
-    # ### end Alembic commands ###
-
-
-def downgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.drop_table('correlation_property_cache')
-    # ### end Alembic commands ###
diff --git a/spiffworkflow-backend/migrations/versions/4ab08bf12666_.py b/spiffworkflow-backend/migrations/versions/9f0b1662a8af_.py
similarity index 75%
rename from spiffworkflow-backend/migrations/versions/4ab08bf12666_.py
rename to spiffworkflow-backend/migrations/versions/9f0b1662a8af_.py
index fcc57315..6f3270f3 100644
--- a/spiffworkflow-backend/migrations/versions/4ab08bf12666_.py
+++ b/spiffworkflow-backend/migrations/versions/9f0b1662a8af_.py
@@ -1,8 +1,8 @@
 """empty message
 
-Revision ID: 4ab08bf12666
-Revises: b581ff2351ad
-Create Date: 2023-02-23 07:25:54.135765
+Revision ID: 9f0b1662a8af
+Revises: 63fc8d693b9f
+Create Date: 2023-02-24 14:30:05.970959
 
 """
 from alembic import op
@@ -10,19 +10,26 @@ import sqlalchemy as sa
 from sqlalchemy.dialects import mysql
 
 # revision identifiers, used by Alembic.
-revision = '4ab08bf12666'
-down_revision = 'b581ff2351ad'
+revision = '9f0b1662a8af'
+down_revision = '63fc8d693b9f'
 branch_labels = None
 depends_on = None
 
 
 def upgrade():
     # ### commands auto generated by Alembic - please adjust! ###
-    op.create_table('message_instance_correlation',
+    op.create_table('correlation_property_cache',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(length=50), nullable=False),
+    sa.Column('message_name', sa.String(length=50), nullable=False),
+    sa.Column('process_model_id', sa.String(length=255), nullable=False),
+    sa.Column('retrieval_expression', sa.String(length=255), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('message_instance_correlation_rule',
     sa.Column('id', sa.Integer(), nullable=False),
     sa.Column('message_instance_id', sa.Integer(), nullable=False),
     sa.Column('name', sa.String(length=50), nullable=False),
-    sa.Column('expected_value', sa.String(length=255), nullable=True),
     sa.Column('retrieval_expression', sa.String(length=255), nullable=True),
     sa.Column('updated_at_in_seconds', sa.Integer(), nullable=True),
     sa.Column('created_at_in_seconds', sa.Integer(), nullable=True),
@@ -30,26 +37,29 @@ def upgrade():
     sa.PrimaryKeyConstraint('id'),
     sa.UniqueConstraint('message_instance_id', 'name', name='message_instance_id_name_unique')
     )
-    op.create_index(op.f('ix_message_instance_correlation_expected_value'), 'message_instance_correlation', ['expected_value'], unique=False)
-    op.create_index(op.f('ix_message_instance_correlation_message_instance_id'), 'message_instance_correlation', ['message_instance_id'], unique=False)
-
-    op.drop_index('ix_message_correlation_property_identifier', table_name='message_correlation_property')
-    op.drop_index('message_correlation_property_unique', table_name='message_correlation_property')
-    op.drop_constraint('message_correlation_ibfk_1', 'message_correlation', type_='foreignkey')
-    op.drop_table('message_correlation_property')
-    op.drop_index('ix_message_correlation_message_correlation_property_id', table_name='message_correlation')
+    op.create_index(op.f('ix_message_instance_correlation_rule_message_instance_id'), 'message_instance_correlation_rule', ['message_instance_id'], unique=False)
+    op.drop_index('ix_message_model_identifier', table_name='message_model')
+    op.drop_index('ix_message_model_name', table_name='message_model')
+    op.drop_constraint('message_correlation_property_ibfk_1', 'message_correlation_property', type_='foreignkey')
+    op.drop_constraint('message_triggerable_process_model_ibfk_1', 'message_triggerable_process_model', type_='foreignkey')
+    op.drop_constraint('message_instance_ibfk_1', 'message_instance', type_='foreignkey')
+    op.drop_table('message_model')
+    op.drop_constraint('message_correlation_message_instance_ibfk_1', 'message_correlation_message_instance', type_='foreignkey')
     op.drop_index('ix_message_correlation_name', table_name='message_correlation')
     op.drop_index('ix_message_correlation_process_instance_id', table_name='message_correlation')
     op.drop_index('ix_message_correlation_value', table_name='message_correlation')
-    op.drop_constraint('message_correlation_message_instance_ibfk_1', 'message_correlation_message_instance', type_='foreignkey')
-    op.drop_constraint('message_triggerable_process_model_ibfk_1', 'message_triggerable_process_model', type_='foreignkey')
+#    op.drop_index('message_instance_id_name_unique', table_name='message_correlation')
+#    op.drop_index('ix_message_correlation_message_correlation_property_id', table_name='message_correlation')
     op.drop_table('message_correlation')
-    op.drop_index('ix_message_model_identifier', table_name='message_model')
-    op.drop_index('ix_message_model_name', table_name='message_model')
-    op.drop_constraint('message_instance_ibfk_1', 'message_instance', type_='foreignkey')
-    op.drop_table('message_model')
+    op.drop_index('ix_message_correlation_message_instance_message_correlation_id', table_name='message_correlation_message_instance')
+    op.drop_index('ix_message_correlation_message_instance_message_instance_id', table_name='message_correlation_message_instance')
+#    op.drop_index('message_correlation_message_instance_unique', table_name='message_correlation_message_instance')
     op.drop_table('message_correlation_message_instance')
+    op.drop_index('ix_message_correlation_property_identifier', table_name='message_correlation_property')
+    op.drop_index('message_correlation_property_unique', table_name='message_correlation_property')
+    op.drop_table('message_correlation_property')
     op.add_column('message_instance', sa.Column('name', sa.String(length=255), nullable=True))
+    op.add_column('message_instance', sa.Column('correlation_keys', sa.JSON(), nullable=True))
     op.add_column('message_instance', sa.Column('user_id', sa.Integer(), nullable=False))
     op.add_column('message_instance', sa.Column('counterpart_id', sa.Integer(), nullable=True))
     op.alter_column('message_instance', 'process_instance_id',
@@ -66,9 +76,8 @@ def upgrade():
 def downgrade():
     # ### commands auto generated by Alembic - please adjust! ###
     op.add_column('message_triggerable_process_model', sa.Column('message_model_id', mysql.INTEGER(), autoincrement=False, nullable=False))
-    op.create_foreign_key('message_triggerable_process_model_ibfk_1', 'message_triggerable_process_model', 'message_model', ['message_model_id'], ['id'])
     op.create_index('message_model_id', 'message_triggerable_process_model', ['message_model_id'], unique=False)
-    op.drop_column('message_triggerable_process_model', 'name')
+    op.drop_column('message_triggerable_process_model', 'message_name')
     op.add_column('message_instance', sa.Column('message_model_id', mysql.INTEGER(), autoincrement=False, nullable=False))
     op.drop_constraint(None, 'message_instance', type_='foreignkey')
     op.create_foreign_key('message_instance_ibfk_1', 'message_instance', 'message_model', ['message_model_id'], ['id'])
@@ -77,28 +86,36 @@ def downgrade():
                nullable=False)
     op.drop_column('message_instance', 'counterpart_id')
     op.drop_column('message_instance', 'user_id')
+    op.drop_column('message_instance', 'correlation_keys')
     op.drop_column('message_instance', 'name')
-    op.create_table('message_correlation_message_instance',
-    sa.Column('message_instance_id', mysql.INTEGER(), autoincrement=False, nullable=False),
-    sa.Column('message_correlation_id', mysql.INTEGER(), autoincrement=False, nullable=False),
-    sa.ForeignKeyConstraint(['message_correlation_id'], ['message_correlation.id'], name='message_correlation_message_instance_ibfk_1'),
-    sa.ForeignKeyConstraint(['message_instance_id'], ['message_instance.id'], name='message_correlation_message_instance_ibfk_2'),
-    sa.PrimaryKeyConstraint('message_instance_id', 'message_correlation_id'),
-    mysql_collate='utf8mb4_0900_ai_ci',
-    mysql_default_charset='utf8mb4',
-    mysql_engine='InnoDB'
-    )
-    op.create_table('message_model',
+    op.create_table('message_correlation_property',
     sa.Column('id', mysql.INTEGER(), autoincrement=True, nullable=False),
     sa.Column('identifier', mysql.VARCHAR(length=50), nullable=True),
-    sa.Column('name', mysql.VARCHAR(length=50), nullable=True),
+    sa.Column('message_model_id', mysql.INTEGER(), autoincrement=False, nullable=False),
+    sa.Column('updated_at_in_seconds', mysql.INTEGER(), autoincrement=False, nullable=True),
+    sa.Column('created_at_in_seconds', mysql.INTEGER(), autoincrement=False, nullable=True),
+    sa.ForeignKeyConstraint(['message_model_id'], ['message_model.id'], name='message_correlation_property_ibfk_1'),
     sa.PrimaryKeyConstraint('id'),
     mysql_collate='utf8mb4_0900_ai_ci',
     mysql_default_charset='utf8mb4',
     mysql_engine='InnoDB'
     )
-    op.create_index('ix_message_model_name', 'message_model', ['name'], unique=False)
-    op.create_index('ix_message_model_identifier', 'message_model', ['identifier'], unique=False)
+    op.create_index('message_correlation_property_unique', 'message_correlation_property', ['identifier', 'message_model_id'], unique=False)
+    op.create_index('ix_message_correlation_property_identifier', 'message_correlation_property', ['identifier'], unique=False)
+    op.create_table('message_correlation_message_instance',
+    sa.Column('id', mysql.INTEGER(), autoincrement=True, nullable=False),
+    sa.Column('message_instance_id', mysql.INTEGER(), autoincrement=False, nullable=False),
+    sa.Column('message_correlation_id', mysql.INTEGER(), autoincrement=False, nullable=False),
+    sa.ForeignKeyConstraint(['message_correlation_id'], ['message_correlation.id'], name='message_correlation_message_instance_ibfk_1'),
+    sa.ForeignKeyConstraint(['message_instance_id'], ['message_instance.id'], name='message_correlation_message_instance_ibfk_2'),
+    sa.PrimaryKeyConstraint('id'),
+    mysql_collate='utf8mb4_0900_ai_ci',
+    mysql_default_charset='utf8mb4',
+    mysql_engine='InnoDB'
+    )
+    op.create_index('message_correlation_message_instance_unique', 'message_correlation_message_instance', ['message_instance_id', 'message_correlation_id'], unique=False)
+    op.create_index('ix_message_correlation_message_instance_message_instance_id', 'message_correlation_message_instance', ['message_instance_id'], unique=False)
+    op.create_index('ix_message_correlation_message_instance_message_correlation_id', 'message_correlation_message_instance', ['message_correlation_id'], unique=False)
     op.create_table('message_correlation',
     sa.Column('id', mysql.INTEGER(), autoincrement=True, nullable=False),
     sa.Column('process_instance_id', mysql.INTEGER(), autoincrement=False, nullable=False),
@@ -119,21 +136,18 @@ def downgrade():
     op.create_index('ix_message_correlation_process_instance_id', 'message_correlation', ['process_instance_id'], unique=False)
     op.create_index('ix_message_correlation_name', 'message_correlation', ['name'], unique=False)
     op.create_index('ix_message_correlation_message_correlation_property_id', 'message_correlation', ['message_correlation_property_id'], unique=False)
-    op.create_table('message_correlation_property',
+    op.create_table('message_model',
     sa.Column('id', mysql.INTEGER(), autoincrement=True, nullable=False),
     sa.Column('identifier', mysql.VARCHAR(length=50), nullable=True),
-    sa.Column('message_model_id', mysql.INTEGER(), autoincrement=False, nullable=False),
-    sa.Column('updated_at_in_seconds', mysql.INTEGER(), autoincrement=False, nullable=True),
-    sa.Column('created_at_in_seconds', mysql.INTEGER(), autoincrement=False, nullable=True),
-    sa.ForeignKeyConstraint(['message_model_id'], ['message_model.id'], name='message_correlation_property_ibfk_1'),
+    sa.Column('name', mysql.VARCHAR(length=50), nullable=True),
     sa.PrimaryKeyConstraint('id'),
     mysql_collate='utf8mb4_0900_ai_ci',
     mysql_default_charset='utf8mb4',
     mysql_engine='InnoDB'
     )
-    op.create_index('message_correlation_property_unique', 'message_correlation_property', ['identifier', 'message_model_id'], unique=False)
-    op.create_index('ix_message_correlation_property_identifier', 'message_correlation_property', ['identifier'], unique=False)
-    op.drop_index(op.f('ix_message_instance_correlation_message_instance_id'), table_name='message_instance_correlation')
-    op.drop_index(op.f('ix_message_instance_correlation_expected_value'), table_name='message_instance_correlation')
-    op.drop_table('message_instance_correlation')
+    op.create_index('ix_message_model_name', 'message_model', ['name'], unique=False)
+    op.create_index('ix_message_model_identifier', 'message_model', ['identifier'], unique=False)
+    op.drop_index(op.f('ix_message_instance_correlation_rule_message_instance_id'), table_name='message_instance_correlation_rule')
+    op.drop_table('message_instance_correlation_rule')
+    op.drop_table('correlation_property_cache')
     # ### end Alembic commands ###
diff --git a/spiffworkflow-backend/migrations/versions/ac40af4ddef3_.py b/spiffworkflow-backend/migrations/versions/ac40af4ddef3_.py
deleted file mode 100644
index c66b35b8..00000000
--- a/spiffworkflow-backend/migrations/versions/ac40af4ddef3_.py
+++ /dev/null
@@ -1,33 +0,0 @@
-"""empty message
-
-Revision ID: ac40af4ddef3
-Revises: 63fc8d693b9f
-Create Date: 2023-02-16 14:54:14.533029
-
-"""
-from alembic import op
-import sqlalchemy as sa
-from sqlalchemy.dialects import mysql
-
-# revision identifiers, used by Alembic.
-revision = 'ac40af4ddef3'
-down_revision = '63fc8d693b9f'
-branch_labels = None
-depends_on = None
-
-
-def upgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.drop_index('message_correlation_message_instance_unique', table_name='message_correlation_message_instance')
-    op.drop_column('message_correlation_message_instance', 'id')
-    op.create_primary_key('mcmi_pirmary_key','message_correlation_message_instance', ['message_instance_id', 'message_correlation_id'])
-    # ### end Alembic commands ###
-
-
-def downgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.add_column('message_correlation_message_instance', sa.Column('id', mysql.INTEGER(), autoincrement=False, nullable=False))
-    op.create_index('message_correlation_message_instance_unique', 'message_correlation_message_instance', ['message_instance_id', 'message_correlation_id'], unique=False)
-    op.create_index('ix_message_correlation_message_instance_message_instance_id', 'message_correlation_message_instance', ['message_instance_id'], unique=False)
-    op.create_index('ix_message_correlation_message_instance_message_correlation_id', 'message_correlation_message_instance', ['message_correlation_id'], unique=False)
-    # ### end Alembic commands ###
diff --git a/spiffworkflow-backend/migrations/versions/b581ff2351ad_.py b/spiffworkflow-backend/migrations/versions/b581ff2351ad_.py
deleted file mode 100644
index 761edee3..00000000
--- a/spiffworkflow-backend/migrations/versions/b581ff2351ad_.py
+++ /dev/null
@@ -1,35 +0,0 @@
-"""empty message
-
-Revision ID: b581ff2351ad
-Revises: ac40af4ddef3
-Create Date: 2023-02-19 11:19:24.371528
-
-"""
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision = 'b581ff2351ad'
-down_revision = 'ac40af4ddef3'
-branch_labels = None
-depends_on = None
-
-
-def upgrade():
-
-    # Just some table cleanup so the join table is properly built
-    op.drop_constraint('message_correlation_message_instance_ibfk_1', 'message_correlation_message_instance', type_="foreignkey")
-    op.drop_constraint('message_correlation_message_instance_ibfk_2', 'message_correlation_message_instance', type_="foreignkey")
-    op.drop_index('ix_message_correlation_message_instance_message_correlation_id', table_name='message_correlation_message_instance')
-    op.drop_index('ix_message_correlation_message_instance_message_instance_id', table_name='message_correlation_message_instance')
-    op.create_foreign_key(None, 'message_correlation_message_instance', 'message_correlation', ['message_correlation_id'], ['id'])
-    op.create_foreign_key(None, 'message_correlation_message_instance', 'message_instance', ['message_instance_id'], ['id'])
-
-
-def downgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.drop_index(op.f('ix_message_correlation_property_correlation_key'), table_name='message_correlation_property')
-    op.create_index('ix_message_correlation_message_instance_message_instance_id', 'message_correlation_message_instance', ['message_instance_id'], unique=False)
-    op.create_index('ix_message_correlation_message_instance_message_correlation_id', 'message_correlation_message_instance', ['message_correlation_id'], unique=False)
-    # ### end Alembic commands ###
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance.py
index 418bc7eb..95f687a3 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance.py
@@ -19,7 +19,7 @@ from spiffworkflow_backend.models.user import UserModel
 
 if TYPE_CHECKING:
     from spiffworkflow_backend.models.message_instance_correlation import (  # noqa: F401
-        MessageInstanceCorrelationModel,
+        MessageInstanceCorrelationRuleModel,
     )
 
 
@@ -49,7 +49,9 @@ class MessageInstanceModel(SpiffworkflowBaseDBModel):
     process_instance_id: int = db.Column(ForeignKey(ProcessInstanceModel.id), nullable=True)  # type: ignore
     name: str = db.Column(db.String(255))
     message_type: str = db.Column(db.String(20), nullable=False)
+    # Only Send Messages have a payload
     payload: dict = db.Column(db.JSON)
+    correlation_keys: dict = db.Column(db.JSON) # The correlation keys of the process at the time the message was created.
     status: str = db.Column(db.String(20), nullable=False, default="ready")
     user_id: int = db.Column(ForeignKey(UserModel.id), nullable=False)  # type: ignore
     user = relationship("UserModel")
@@ -59,8 +61,8 @@ class MessageInstanceModel(SpiffworkflowBaseDBModel):
     failure_cause: str = db.Column(db.Text())
     updated_at_in_seconds: int = db.Column(db.Integer)
     created_at_in_seconds: int = db.Column(db.Integer)
-    correlations = relationship(
-        "MessageInstanceCorrelationModel", back_populates="message_instance"
+    correlation_rules = relationship(
+        "MessageInstanceCorrelationRuleModel", back_populates="message_instance"
     )
 
     @validates("message_type")
@@ -74,40 +76,59 @@ class MessageInstanceModel(SpiffworkflowBaseDBModel):
         return self.validate_enum_field(key, value, MessageStatuses)
 
     def correlates(
-        self, other_message_instance: Any, expression_engine: PythonScriptEngine
+        self, other: Any, expression_engine: PythonScriptEngine
     ) -> bool:
-        # This must be a receive message, and the other must be a send (otherwise we reverse the call)
-        # We evaluate the other messages payload and run our correlation's
-        # retrieval expressions against it, then compare it against our
-        # expected values -- IF we don't have an expected value, we accept
-        # any non-erroring result from the retrieval expression.
-        if self.name != other_message_instance.name:
+        """ Returns true if the this Message correlates with the given message.
+
+         This must be a 'receive' message, and the other must be a 'send' or vice/versa. We evaluate
+         the other messages payload and run our correlation's retrieval expressions against it, then
+          compare it against our expected values (as stored in this messages' correlation_keys)
+         IF we don't have an expected value, we accept any non-error result from the retrieval
+         expression. """
+        if self.is_send() and other.is_receive():
+            # Flip the call.
+            return other.correlates(self, expression_engine)  # type: ignore
+
+        if self.name != other.name:
             return False
-        if self.message_type == MessageTypes.receive.value:
-            if other_message_instance.message_type != MessageTypes.send.value:
-                return False
-            payload = other_message_instance.payload
-            for corr in self.correlations:
-                try:
-                    result = expression_engine._evaluate(
-                        corr.retrieval_expression, payload
-                    )
-                except Exception:
-                    # the failure of a payload evaluation may not mean that matches for these
-                    # message instances can't happen with other messages.  So don't error up.
-                    # fixme:  Perhaps log some sort of error.
-                    return False
-                if corr.expected_value is None:
-                    continue  # We will accept any value
-                elif corr.expected_value != str(
-                    result
-                ):  # fixme:  Don't require conversion to string
-                    return False
+        if not self.is_receive():
+            return False
+        if isinstance(self.correlation_keys, dict) and self.correlation_keys == other.correlation_keys:
+            # We know we have a match, and we can just return if we don't have to figure out the key
             return True
-        elif other_message_instance.message_type == MessageTypes.receive.value:
-            return other_message_instance.correlates(self, expression_engine)  # type: ignore
+
+        # Loop over the receives' correlation keys - if any of the keys fully match, then we match.
+        for expected_values in self.correlation_keys.values():
+            if self.payload_matches_expected_values(other.payload, expected_values, expression_engine):
+                return True
         return False
 
+    def is_receive(self):
+        return self.message_type == MessageTypes.receive.value
+
+    def is_send(self):
+        return self.message_type == MessageTypes.send.value
+
+    def payload_matches_expected_values(
+            self, payload: dict,
+            expected_values: dict,
+            expression_engine: PythonScriptEngine) -> bool:
+        """Compares the payload of a 'send' message against a single correlation key's expected values."""
+        for correlation_key in self.correlation_rules:
+            expected_value = expected_values.get(correlation_key.name, None)
+            if expected_value is None: # This key is not required for this instance to match.
+                continue
+            try:
+                result = expression_engine._evaluate(correlation_key.retrieval_expression, payload)
+            except Exception:
+                # the failure of a payload evaluation may not mean that matches for these
+                # message instances can't happen with other messages.  So don't error up.
+                # fixme:  Perhaps log some sort of error.
+                return False
+            if result != expected_value:
+                return False
+        return True
+
 
 # This runs for ALL db flushes for ANY model, not just this one even if it's in the MessageInstanceModel class
 # so this may not be worth it or there may be a better way to do it
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance_correlation.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance_correlation.py
index 024d3bca..7431a273 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance_correlation.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/message_instance_correlation.py
@@ -10,16 +10,16 @@ from spiffworkflow_backend.models.message_instance import MessageInstanceModel
 
 
 @dataclass
-class MessageInstanceCorrelationModel(SpiffworkflowBaseDBModel):
+class MessageInstanceCorrelationRuleModel(SpiffworkflowBaseDBModel):
     """These are the correlations of a specific Message Instance.
 
     These will only exist on receive messages. It provides the expression to run on
-    a send messages payload which must match the expected value to be considered
-    a valid match.  If the expected value is null, then it does not need to
+    a send messages payload which must match receive messages correlation_key dictionary
+     to be considered a valid match.  If the expected value is null, then it does not need to
     match, but the expression should still evaluate and produce a result.
     """
 
-    __tablename__ = "message_instance_correlation"
+    __tablename__ = "message_instance_correlation_rule"
     __table_args__ = (
         db.UniqueConstraint(
             "message_instance_id",
@@ -33,10 +33,9 @@ class MessageInstanceCorrelationModel(SpiffworkflowBaseDBModel):
         ForeignKey(MessageInstanceModel.id), nullable=False, index=True  # type: ignore
     )
     name: str = db.Column(db.String(50), nullable=False)
-    expected_value: str = db.Column(db.String(255), nullable=True, index=True)
     retrieval_expression: str = db.Column(db.String(255))
     updated_at_in_seconds: int = db.Column(db.Integer)
     created_at_in_seconds: int = db.Column(db.Integer)
     message_instance = relationship(
-        "MessageInstanceModel", back_populates="correlations"
+        "MessageInstanceModel", back_populates="correlation_rules"
     )
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/routes/messages_controller.py b/spiffworkflow-backend/src/spiffworkflow_backend/routes/messages_controller.py
index 8821630c..1c86fddb 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/routes/messages_controller.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/routes/messages_controller.py
@@ -86,7 +86,6 @@ def message_send(
         name=message_name,
         payload=body["payload"],
         user_id=g.user.id,
-        correlations=[],
     )
     db.session.add(message_instance)
     db.session.commit()
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/error_handling_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/error_handling_service.py
index e335ab6f..56b3f547 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/error_handling_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/error_handling_service.py
@@ -94,8 +94,7 @@ class ErrorHandlingService:
             message_type="send",
             name=message_name,
             payload=message_payload,
-            user_id=g.user.id,
-            correlations=[],
+            user_id=g.user.id
         )
         db.session.add(message_instance)
         db.session.commit()
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py
index 39ee5968..51f6ba81 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py
@@ -62,7 +62,7 @@ from spiffworkflow_backend.models.human_task import HumanTaskModel
 from spiffworkflow_backend.models.human_task_user import HumanTaskUserModel
 from spiffworkflow_backend.models.message_instance import MessageInstanceModel
 from spiffworkflow_backend.models.message_instance_correlation import (
-    MessageInstanceCorrelationModel,
+    MessageInstanceCorrelationRuleModel
 )
 from spiffworkflow_backend.models.process_instance import ProcessInstanceModel
 from spiffworkflow_backend.models.process_instance import ProcessInstanceStatus
@@ -1352,7 +1352,7 @@ class ProcessInstanceProcessor:
                 message_type="send",
                 name=bpmn_message.name,
                 payload=bpmn_message.payload,
-                correlations=[],
+                correlation_keys=self.bpmn_process_instance.correlations
             )
             db.session.add(message_instance)
             db.session.commit()
@@ -1382,15 +1382,15 @@ class ProcessInstanceProcessor:
                 user_id=self.process_instance_model.process_initiator_id,
                 message_type="receive",
                 name=event["name"],
+                correlation_keys=self.bpmn_process_instance.correlations
             )
             for correlation_property in event["value"]:
-                message_correlation = MessageInstanceCorrelationModel(
+                message_correlation = MessageInstanceCorrelationRuleModel(
                     message_instance_id=message_instance.id,
                     name=correlation_property.name,
-                    expected_value=correlation_property.expected_value,
                     retrieval_expression=correlation_property.retrieval_expression,
                 )
-                message_instance.correlations.append(message_correlation)
+                message_instance.correlation_rules.append(message_correlation)
             db.session.add(message_instance)
             db.session.commit()
 
diff --git a/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_instance.py b/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_instance.py
index a216cd28..b48bc239 100644
--- a/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_instance.py
+++ b/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_instance.py
@@ -54,7 +54,7 @@ class TestMessageInstance(BaseTest):
             user_id=process_instance.process_initiator_id,
             message_type="send",
             name=message_name,
-            payload={"Word": "Eat At Mashita's, delicious!"},
+            payload={"Word": "Eat At Mashita's, its delicious!"},
         )
         db.session.add(queued_message)
         db.session.commit()
diff --git a/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_service.py b/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_service.py
index d262931a..986951e9 100644
--- a/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_service.py
+++ b/spiffworkflow-backend/tests/spiffworkflow_backend/unit/test_message_service.py
@@ -43,7 +43,7 @@ class TestMessageService(BaseTest):
             "amount": "100.00",
         }
 
-        self.start_sender_process(client, with_super_admin_user)
+        self.start_sender_process(client, with_super_admin_user, "test_from_api")
         self.assure_a_message_was_sent()
         self.assure_there_is_a_process_waiting_on_a_message()
 
@@ -105,7 +105,7 @@ class TestMessageService(BaseTest):
         )
 
         # Now start the main process
-        self.start_sender_process(client, with_super_admin_user)
+        self.start_sender_process(client, with_super_admin_user, "test_between_processes")
         self.assure_a_message_was_sent()
 
         # This is typically called in a background cron process, so we will manually call it
@@ -145,9 +145,9 @@ class TestMessageService(BaseTest):
         assert message_receiver_process.status == "complete"
 
     def start_sender_process(
-        self, client: FlaskClient, with_super_admin_user: UserModel
+        self, client: FlaskClient, with_super_admin_user: UserModel, group_name:str = "test_group"
     ) -> None:
-        process_group_id = "test_group"
+        process_group_id = group_name
         self.create_process_group(
             client, with_super_admin_user, process_group_id, process_group_id
         )
@@ -186,7 +186,7 @@ class TestMessageService(BaseTest):
         assert len(send_messages) == 1
         send_message = send_messages[0]
         assert (
-            send_message.payload == self.payload
+                send_message.payload == self.payload
         ), "The send message should match up with the payload"
         assert send_message.name == "Request Approval"
         assert send_message.status == "ready"
@@ -207,12 +207,10 @@ class TestMessageService(BaseTest):
         self, message: MessageInstanceModel
     ) -> None:
         # Correlation Properties should match up
-        po_curr = next(c for c in message.correlations if c.name == "po_number")
-        customer_curr = next(c for c in message.correlations if c.name == "customer_id")
+        po_curr = next(c for c in message.correlation_rules if c.name == "po_number")
+        customer_curr = next(c for c in message.correlation_rules if c.name == "customer_id")
         assert po_curr is not None
         assert customer_curr is not None
-        assert po_curr.expected_value == "1001"
-        assert customer_curr.expected_value == "Sartography"
 
     def test_can_send_message_to_multiple_process_models(
         self,