nemesis
No, WoW will need to be in the foreground of every computer. While it is possible to inject input into a background process it gets ever closer to automation and crosses a line that I am not willing to cross. Playing a game that isn't the active application looks way too much like a bot for my taste.

Rowan
One option for stopping movement is to bind a key to stop on each of the client computers that you can press when you are ready for them to stop. Unfortunately you can't put it into a macro that I know of.