Set Matte Effect

[PixelDeluxe]

Would it be possible for the devs to add in a Set Matte effect that works like After Effect's Set Matte effect?

I use Photoshop to composite together V-Ray EXR passes for product renders, and regularly use RGB multimatte passes for isolating different shaders or models. Having a Set Matte effect that can use different Multimatte passes automatically via some easy linking system to the RGB of another layer, without me having to create masks manually via the channels would be a huge timesaver!