disable/re-task GM

I have not been able to find a workable solution for this but I would like the ability to either disable or re-task the GM to reduce a common user error that my volunteers tend to run into often. It would be helpful if I could do that, in particular with a playback wing. I have a FB4 with a PB wing 4. Another option if possible maybe to re-task the GM as a House light fader and maybe even use on screen keys to change between different setup of those houselights (like when the room is not full and I need to dim the outside or FOH houselights. Just my 2 cents. I realize that could give me 2 house light faders but at least they are synched together with the motorized faders.