Yes! This is perfect!

I'm guessing this is only a features of Arena 6. (I'm currently running Arena 5)... Thus why I couldn't find that option?

Hello! I've been stacking 2 projectors (for output) making duplicate slices for each of the projectors, then warping the outputs for alignment. I've been pretty happy with the results. (It fits my need, as the 2 projectors are different resolutions and doing a manual/physical alignment of the pixels...