typically i dont think theres an issue if they are just "touching"...
i have thought of intentionally attaching zoos to clam shells (just another piece of unused realestate) just like in clkwrk's pic, but was concerned that in the long run the zoos might try to spread over the edge onto the inside of the shell, thus creating a problem that would probably result in the death of the clam????
anyone had zoos on a clam for the long term? have you had zoos fully cover a clam shell and just stop there? as in they didnt try to spread over the edge?