I think on board with this logic even though I've never tried it.

It doesn't matter whether you have a zigbee antenna or not. When a remote communicates via zigbee it will output IR and if you have system macros you can create hex and have one processor send the IR signal to another which will issue a system macro (with a two conductor). If you could get three wires between the processors you could send/receive IR between the two processors. I don't think multiple processors create the same trigger code for a given system macro within the same system file but I would stay away from create two different system files because I don't know if those trigger codes would ever be the same for each file.