[Zope-dev] Object ID changed after modify

I just found out the object id is changed if It got updated/ If I want an object appear in different parts of the OODB. say, I got a person which joints several groups and thus have several appearence in the oodb. If the person updated his information, and his id got changed. How could I represent hime in zope? Is it impossible to have links of the object in different parts of the tree? Rgs, Kent Sin