4 VGA input multiplexer (4-PC's displayed simultaniously on 1 monitor)

Is there such a device that will allow the simultanious display of 4
VGA (800 * 600 *256colour) on a 19"TFT monitor ( capable of 1600 *
1200 ). This would be similar to the Security Video displays that
allow viewing of several video inputs on 1 monitor. A standard KVM
switch is not usefull in the application because all screens need to
be viewed at the same time.

Any ideas of a work around would also be appreciated.


Thanks,
Scott.B.