diff --git a/panda/src/collide/collisionHandlerEvent.cxx b/panda/src/collide/collisionHandlerEvent.cxx
index ad1ad61a3c..31b0267612 100644
--- a/panda/src/collide/collisionHandlerEvent.cxx
+++ b/panda/src/collide/collisionHandlerEvent.cxx
@@ -162,6 +162,17 @@ clear() {
   _current_colliding.clear();
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: CollisionHandlerEvent::flush
+//       Access: Public
+//  Description: Same as clear() except "out" events are thrown.
+////////////////////////////////////////////////////////////////////
+void CollisionHandlerEvent::
+flush() {
+  begin_group();
+  end_group();
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: CollisionHandlerEvent::throw_event_for
 //       Access: Private
diff --git a/panda/src/collide/collisionHandlerEvent.h b/panda/src/collide/collisionHandlerEvent.h
index 91c6384e19..c59a549618 100644
--- a/panda/src/collide/collisionHandlerEvent.h
+++ b/panda/src/collide/collisionHandlerEvent.h
@@ -66,6 +66,7 @@ PUBLISHED:
   INLINE string get_out_pattern(int n) const;
 
   void clear();
+  void flush();
 
 protected:
   void throw_event_for(const vector_string &patterns, CollisionEntry *entry);