Implementing a weak reference in Matlab

When someone makes a request for an object with certain parameters, I'd like to return an existing object (of handle type) if the parameters match accordingly. Unfortunately, if the object server holds onto the object so that it can be returned instead of a new object, the object will never be cleared. If the object server is the only thing holding onto the object, then I want it to be cleared.

Is this possible?

[Jim Hokanson]

Also asked on SO: https://stackoverflow.com/questions/4463254/matlab-weak-references-to-handle-class-objects