[Twisted-Python] Unjellying and circular references?

I'm using perspective broker to transfer objects in a networked game, which I'm having trouble unjellying -- the remote versions wind up with dangling twisted.persisted.crefutil._Dereference instances, so don't match the original objects. I'm seeing this for objects that have circular references to each other. I've refactored things to mostly avoid circular references and sidestep this, but have one remaining case where I find circular references mean clearer code that I'm reluctant to refactor. Is there some trick I'm missing to avoid _Dereferences?