Multiple outputs & GPU

I want to use 3 different outputs for some of my stuff.
What I want to do is take the output of a renderer at 2400x600 and use it as a dx texture to spread it over 3 renderers which each use 800px x 600px and output these through the 3 cards’ composite output.
My question is, with a setup like this which GPU does the processing of the main 2400x600 output?

I have an nvidia 7900gt but it has only 1 composite output and 2 dvi’s, I could get VGA-composite converters but I can’t do triple head with the card anyway so that wouldn’t work.
I could get a couple of 6200’s and use their composite outputs with the described method, would that work? And is it possible to make the 7900GT do all of the hard work while the 6200’s just output a quad with the texture?

How does vvvv handle multiple (non sli) graphic cards?

Any help would be much appreciated.

best way to go should be the matrox triplehead2go. Costs some money, but saves you all the bus bandwidth which you lose when you add more GPUs to a system. That way you can do it all in a single renderer, which burns much less CPU.No need to to all the bitBlitting of spreading it out onto 3 renderers, or even on different cards.

if you absolutely need composite instead of vga, better to use an external converter (perhaps 50$ on ebay).
3 GPUs in one PC definitely is a downer for the bandwith, you couldn’t make one device do the “hard work” and then distribute the textures, either - and there are hardly any moBos up to that task.

Well offcourse I’d love to be able to use my dvi or vga output but the place only has composite.
I’ve now completed a test setup and it’s working nicely, the stuff I’ve made is pretty simple anyway, no ‘real’ 3d stuff, I use 2d images in 3d space.
That triplehead2go certainly looks interesting, but tonight I’m gonna use my current setup and see how it goes.
Thanks for the answer, I’ll let you know how it goes