Hi Scott...

Seems to me that there is a way for you to be able to do this..

You can switch from the desk with DMX different Submix settings, allowing you to switch between 1 or more submixes, with different settings.

You say you have 3 shows running, so you can apply 3 different submixes for every output and simply activate them by DMX.. You have to use the mix layer select for this. You basicly tell each submix which layers will be routed to it. In HOG 3 there are even personality's for it...

Don't know which version you are running, but in build m165 it will work..
Hope you manage to do it this way...