diff --git a/wallace/models.py b/wallace/models.py
index <HASH>..<HASH> 100644
--- a/wallace/models.py
+++ b/wallace/models.py
@@ -83,12 +83,14 @@ class Node(Base):
     @property
     def successors2(self):
         outgoing_vectors = Vector.query.filter_by(origin=self).all()
-        return [v.destination for v in outgoing_vectors]
+        return [v.destination for v in outgoing_vectors
+                if isinstance(v.destination, Agent)]
 
     @property
     def predecessors2(self):
         incoming_vectors = Vector.query.filter_by(destination=self).all()
-        return [v.origin for v in incoming_vectors]
+        return [v.origin for v in incoming_vectors
+                if isinstance(v.origin, Agent)]
 
     def __repr__(self):
         return "Node-{}-{}".format(self.uuid[:6], self.type)
predecessors2 should return only Agents