priorities

If you're using some sort of IPC, why not TCP? Then it opens the option of running remote battle runners.

This could actually work really smoothly. By default, it spins up the processes as now, but passing a port number to each process and communicating over TCP/IP. The data sent / received could remain the same. Then we could add command line arguments for:

1. Launching Robocode processes and doing nothing, just listening for commands.
2. Accepting a list of host:port of additional processes. In addition to the normal processes, launch a thread for each remote process.

So on your extra machine, you do #1, and on your primary machine you do #2, and voila!

Edit: Except for copying the necessary bot JARs. That would be a little more complicated.