X10 on a LAN. Easy. Install Active Home Pro and the CM15A interface on the server, and set everything up (modules, timers, macros, etc.) and make sure AHP does what you want it to to.
Then share it. Workstations will be able to run AHP from their PC's. On the server, permisions should allow only operation, not changes.
Of course, the next question is "Why do you want to do it?".