Perplexing....(infinity problem)

Sooo....i was wondering if anyone can give me a answer to this. I'm building a molecule maker for the students in my college. Its nothing specific, they can make three things:
A = # of central atoms
X = # of attached atoms
E = # of lone pairs on central atom
When they grab an X and touch an A with it they combine(rez) to make AX and vise versa. They can also grab some tweezers and touch the AX to make it back into A, and on and on. So, you probably know the problem. This becomes and infinite loop back and forth because AX needs to be inside A but A aslo needs to be inside AX and I don't know were to start. I don't think think its possible...but if you know a way to do it, HALP PLS. I have also thought of the the idea of just rezzing the links instead of a whole other molecule, but getting the angles might be alittle hard.

Heres a link to the angles:
http://employees.csbsju.edu/hjakubowski/classes/ch123/Bonding/vsepr.gif

Thanks to anyone that can help.

Easiest is to put all the atoms inside the base and have them send a message back to the base asking it to rez a new atom in the appropriate position and rotation.

......WOW, that is a nice fix, thanks. I'll try it out.

*EDIT* Thank you very much that worked splendedly.