You could make a 16 part "Layered Performance" drum set with each part consisting of a User Patch consisting of up to 4 tones, couldn't you? That is, use the individual waveforms on the B&D board to create a User Patch (up to 4 waveforms)...save to User/Internal Memory, of course...and do this for up to 16 different hits/patches...then, use all 16 User Patches in a User Performance (Layer Key Mode) and map them out across the keyboard how you want.

Is that what you were thinking?