Actually the boards the support this tend to do so over MIDI, the problem is yours just doesn't support this. Otherwise I could make suggestions as I have done similar things in the past with consoles that do. So the programming mute scenes etc. isn't difficult, the hardware to support this however is expensive, and yes is typically expensive because it typically eneds ot do much more than simple mute and unmute.
pleas do come up with a suggestions. It would be nice if I could give the Board a kind of answer to how this can be done. Then they can decide how much money they whant to spend on it. Maybe it can be put into the next year's budget