diff --git a/abc/past.nim b/abc/past.nim
index 78d8422..bde5f22 100644
--- a/abc/past.nim
+++ b/abc/past.nim
@@ -18,3 +18,7 @@ func past(store: TxStore, ackHash: AckHash, accumulator: var seq[TxHash]) =
 
 func past*(store: TxStore, hash: TxHash|AckHash): seq[TxHash] =
   store.past(hash, result)
+
+func past*(store: TxStore, hashes: varargs[AckHash]): seq[TxHash] =
+  for hash in hashes:
+    store.past(hash, result)
diff --git a/tests/abc/testPast.nim b/tests/abc/testPast.nim
index 0dcc15b..eef4a3a 100644
--- a/tests/abc/testPast.nim
+++ b/tests/abc/testPast.nim
@@ -10,7 +10,7 @@ suite "Past transactions and acknowledgements":
   let bob = PublicKey.bob
   let victor = PublicKey.victor
   var tx1, tx2, tx3: Transaction
-  var ack1, ack2: Ack
+  var ack1, ack2, ack3: Ack
 
   setup:
     tx1 = !Transaction.init({genesis.hash: alice}, {bob: 100.u256}, victor)
@@ -20,8 +20,9 @@ suite "Past transactions and acknowledgements":
       {alice: 200.u256},
       victor
     )
-    ack1 = !Ack.init([tx1.hash, tx2.hash], victor)
-    ack2 = !Ack.init(ack1.hash, [tx3.hash], victor)
+    ack1 = !Ack.init([tx1.hash], victor)
+    ack2 = !Ack.init([tx2.hash], victor)
+    ack3 = !Ack.init(ack1.hash, [tx2.hash, tx3.hash], victor)
 
   test "finds all transactions that precede a transaction":
     var store = TxStore.init(genesis)
@@ -37,6 +38,13 @@ suite "Past transactions and acknowledgements":
   test "finds all transactions that precede an acknowledgement":
     var store = TxStore.init(genesis)
     store.add(tx1, tx2, tx3)
-    store.add(ack1, ack2)
-    check store.past(ack1.hash) == [tx1.hash, genesis.hash, tx2.hash]
-    check store.past(ack2.hash) == [tx1.hash, genesis.hash, tx2.hash, tx3.hash]
+    store.add(ack1, ack2, ack3)
+    check store.past(ack1.hash) == [tx1.hash, genesis.hash]
+    check store.past(ack2.hash) == [tx2.hash, genesis.hash]
+    check store.past(ack3.hash) == [tx1.hash, genesis.hash, tx2.hash, tx3.hash]
+
+  test "finds all transactions that precede a set of acknowledgements":
+    var store = TxStore.init(genesis)
+    store.add(tx1, tx2, tx3)
+    store.add(ack1, ack2, ack3)
+    check store.past(ack1.hash, ack2.hash) == [tx1.hash, genesis.hash, tx2.hash]