Well, If I had this all running on the same PC, (I'm not worrying about bandwidth yet, just engine limitations in one game) I would have the server check a text file shared by all of the servers to get the information.
If only we had badspots power, for a possible engine change, or the holy solution, a big pwnage /512 server.
If I did say, 5 servers for an rpg, make them each 32 players, the game could have up to 160 players, (evenly distributed)