I multi 3 priests in ROM - All you need to do is go into the Key Bindings settings and change QWEASD to UNBOUND...or other (unused) keys. I personally use the arrow keys, bind my main to that to move around and use AutoHotKey to set the arrow keys to "do not pass" to the slave/clients.

Turning on click-to-move is good anyway because it helps your team to auto-rotate to face their targets...