My python product code is structured somewhat like this: class A: __init__ (self, connection_id) self.B = B(connection_id) self.C = C(connection_id) self.sqlquery = SQL(... class B: __init__ (self, connection_id) self.connection_id = connection_id self.sqlquery=SQL(... class C: __init__ (self, connection_id) self.connection_id = connection_id self.sqlquery=SQL(... def manage_addA(self, id, connection_id): ob = A(connection_id) self._setObject(id, ob) This works: Zope/instanceA/sqlquery now trying to do this from Zope, Zope/instanceA/B/sqlquery yields an error message that connection_id chosen is not available. What am I missing? Any workarounds?