APC has software that can sit on the server connected to the UPS (through the serial port) It can then notify the other servers to shutdown if needed. I beleive you want the APC PowerChure Network ...
Power in my house is awkward. Unreliable for starters, hence the UPS, but also sparse. So I have 1 socket into which I have plugged 1 UPS, but I'd like to use it to power down 2 devices: 1 being my PC ...