3 projector installation

hello to all, i would like to make an installation with one big big screen that is filled with three projectors, and io would like to take the same image but different part of it in each projector, i stay looking around how to get it, and the matrox card i useful for me, but the problem i that i need to use a composite signal , is there any hardware that allows me three video outpus, or its better that i try with a multigpu setup with three video cards?? any help please?? in this case, how can i get to output from vvvv one renderer to each output ??

why not using matrox triplehead + 3 vga to composite cables? (you need composite for the projectors, right?)

i’d still go for one renderer streched over the three outputs. avoids troubles with (video)textures on different heads.