Can you specify the address that any coins should be sent to or are they just sent to an address generated in your *coind?
They go to the coind wallet unfortunately. There's no easy way to adjust that on the fly since the wallets themselves don't support it.
One could perhaps hack the wallet's API call for getblocktemplate to take an extra "payment address" parameter, and block that into the template returned. This way different miners could get different merged work.