Scart Switching

I am doing a school project (I'm a teacher not a student!) and want to be able to switch SCART inputs via arduino. The TV I have only has a single SCART socket, so the three input devices (N64, PS2 and PC) will have to come through some sort of switching device. I could get one of the "dumb" devices, but they can only have one on at a time (all three will be powered up) amd I've seen some with push-button switches (http://www.ebay.co.uk/itm/3-WAY-SCART-LEAD-SPLITTER-BOX-1to3-SOCKET-MANUAL-SWITCH-/160995098081?pt=UK_Computing_Sound_Vision_Video_Cables_Adapters&hash=item257c0e3de1) but can't think of an elegant (and cheap) way to automate that. Ideally I'd like to just push positive down a pin and have the attached scart connection come live.

Any suggestions?

Go to http://en.wikipedia.org/wiki/SCART and look at what pin 8 does. By varying the voltage on that pin you can blank the SCART input.