What some of us do with the big mixers is re-steer things such that each input pot controls the level as usual, but each control switch keys a different TX.
Audio output is fed to all TX thru an audio DA. That way you can set audio levels as needed and leave them where you like.
Another use of the facility is switchable multiple monitor inputs, routed to various RX in the shack. Muting is taken care of that way, and listening levels are easily controlled.
Puts a whole new spin on QSY.
If one is lucky to have multiple rigs, that is.
73DG