Three different RGB mattes from a single shading group material ID?

[SonyBoy]

I'm sure there is a way to do this that I'm overlooking. I have a scene containing jelly beans which have seven different colors, but they share a single mesh and shader and the seven colors is controlled with a sampler info node's random by poly shell attr. plugged into a ramp. I want to output RGB mattes for each of the seven colors, meaning I need three RGB passes. I can generate the first one no problem by duplicating the connected color ramp, setting the first three indices to R, G and B, the remaining four colors to black, and plugging this into the overall shader's material ID node. But how can I then generate the next two matte passes using similar methodology, since the SG can only have one material ID? Is there another way to do this?

[SonyBoy]

Doh. Seems like a simple extraTex will work.