I thought about this last night, and tried to think of a way to use masks to increase saturation..
this is what I came up with:
making 3 BW separations, and making a reversed copy of each, then printing each BW separation to a fresh piece of BW film and substracting (or adding, didn't figure out that yet) the other two reversed copies so that in the end you have 3 fresh BW layers each containing a sort of a "difference" between the layer it was supose to show and the two other layers combined.
Would be like bustracting the other two layers from each layer of the color image
Would that work?