It would really depend on the setup.
If its just a standard VGA cable from the monitor to the PC, and USB or PS2 keyb and mouse, then there is no reason why it would.
If its running something different then I probably wouldn't. The KVM's are quite simple and share different computers between 1 keyboard and mouse.
On my desk at work, I'm running a MacBook Pro, 1 x HP laptop and 2 x other PC's all via a KVM to 1 x screen & keyb.