diff --git a/makina-compiler/src/xyz/colinholzman/makina/StateConfiguration.kt b/makina-compiler/src/xyz/colinholzman/makina/StateConfiguration.kt
index c0cbfcb..41478d3 100644
--- a/makina-compiler/src/xyz/colinholzman/makina/StateConfiguration.kt
+++ b/makina-compiler/src/xyz/colinholzman/makina/StateConfiguration.kt
@@ -18,7 +18,7 @@ data class StateConfiguration(val states: Set<State>) {
     }
 
     //Returns the list of handlers that this state configuration should handle.
-    //The handlers are deepest deepest state first and in document order for handlers within a single state.
+    //The handlers are deepest state first and in document order for handlers within a single state.
     fun getHandlers(): List<Pair<State, Handler.Event>> {
         return orderedStates.flatMap { state -> state.handlers.filterIsInstance<Handler.Event>().map { Pair(state, it) } }
     }
@@ -32,4 +32,13 @@ data class StateConfiguration(val states: Set<State>) {
     fun getLeafState(): State {
         return orderedStates.first()
     }
+
+    companion object {
+        fun List<Pair<State, Handler.Event>>.groupByIdAndRemoveRedundantHandlers(): Map<String, List<Pair<State, Handler.Event>>> {
+            return groupBy { it.second.id }.mapValues { entry ->
+                val guards = HashSet<String?>()
+                entry.value.filter { guards.add(it.second.guard) }
+            }
+        }
+    }
 }
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diff --git a/makina-compiler/test/xyz/colinholzman/makina/StateConfigurationTest.kt b/makina-compiler/test/xyz/colinholzman/makina/StateConfigurationTest.kt
index 00ca6bc..d3f9178 100644
--- a/makina-compiler/test/xyz/colinholzman/makina/StateConfigurationTest.kt
+++ b/makina-compiler/test/xyz/colinholzman/makina/StateConfigurationTest.kt
@@ -4,6 +4,10 @@ import org.junit.jupiter.api.Test
 
 import org.junit.jupiter.api.Assertions.*
 import org.junit.jupiter.api.assertThrows
+import xyz.colinholzman.makina.StateConfiguration.Companion.groupByIdAndRemoveRedundantHandlers
+import xyz.colinholzman.makina.TestStates.Companion.s1
+import xyz.colinholzman.makina.TestStates.Companion.s11
+import xyz.colinholzman.makina.TestStates.Companion.s111
 
 internal class StateConfigurationTest {
 
@@ -49,4 +53,46 @@ internal class StateConfigurationTest {
         val config = StateConfiguration(setOf(child, parent))
         assertEquals(child, config.getLeafState())
     }
+
+    @Test
+    fun filterHandlers() {
+        var handlers = arrayListOf(
+                Pair(s111, Handler.Event("foo")),
+                Pair(s11, Handler.Event("foo")),
+                Pair(s1, Handler.Event("foo"))
+        )
+        var expected = mapOf(Pair("foo", listOf(Pair(s111, Handler.Event("foo")))))
+        assertEquals(expected, handlers.groupByIdAndRemoveRedundantHandlers())
+
+
+        handlers = arrayListOf(
+                Pair(s111, Handler.Event("foo")),
+                Pair(s11, Handler.Event("foo")),
+                Pair(s1, Handler.Event("foo", guard = "bar"))
+        )
+        expected = mapOf(Pair("foo", listOf(Pair(s111, Handler.Event("foo")),
+                                            Pair(s1, Handler.Event("foo", guard = "bar")))))
+        assertEquals(expected, handlers.groupByIdAndRemoveRedundantHandlers())
+
+
+        handlers = arrayListOf(
+                Pair(s111, Handler.Event("foo")),
+                Pair(s11, Handler.Event("bar")),
+                Pair(s1, Handler.Event("foo"))
+        )
+        expected = mapOf(Pair("foo", listOf(Pair(s111, Handler.Event("foo")))),
+                         Pair("bar", listOf(Pair(s11, Handler.Event("bar")))))
+        assertEquals(expected, handlers.groupByIdAndRemoveRedundantHandlers())
+
+
+        handlers = arrayListOf(
+                Pair(s111, Handler.Event("foo", guard = "bar")),
+                Pair(s11, Handler.Event("foo", guard = "baz")),
+                Pair(s1, Handler.Event("foo"))
+        )
+        expected = mapOf(Pair("foo", listOf(Pair(s111, Handler.Event("foo", guard = "bar")),
+                                            Pair(s11, Handler.Event("foo", guard = "baz")),
+                                            Pair(s1, Handler.Event("foo")))))
+        assertEquals(expected, handlers.groupByIdAndRemoveRedundantHandlers())
+    }
 }
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