I was wondering how I could send a message, or signal all users of the same system, that they needed to get out of the system for a few minutes for maintenance purposes? Has anyone done this?

The executable for the system is run from each person's own workstation, so it is not a common executable run from the network.

I was thinking that you could do a polling type thing and if a file were checked, say on the network, and once it appeared, the workstation executable would open that file and display the message that was sent, no matter what form was up, etc. Does that seem feasible?