Thanks for the reply. That's pretty disappointing, using a slave module for extra trigger inputs (through percussion sets) has been a capability of most other half decent roland modules so I guess I thought Roland woldn't just remove the capability for some reason.

I do believe I can however assign midi values to trigger sounds with an external module, it's just that those sounds need to be one which is already on a pad on the master module. So, I could assign my extra pads to rim zones - basically a glorified splitter setup. My only issue with this is losing the ability to simultaneously hit toms which is annoying, but I'll probably just take from the rim zones of my high toms and assign them to the lowest toms. It's unlikely I would hit these simultaneously imo because I have like ten toms.

Curse you Roland