Reduce LR stereo field

Working mainly on the ipad app in larger stages i would like a way to open/close the LR stereo field without having to redo the panning for every channel.

In my shows only kick snare and main vocal is in center everything else is a bit panned and especially guitars that i pan back to center for solos.

Since the panning control in the app is not the most accurate instead of trying to fine tune it from there i think it would be better to have a “LR Width” single nob control to close or open the whole stero field mantaining the relative pan of the instruments.

Maybe it’s already possible and i’m not aware of it, in that case sorry for the post and let me please know how to do it.

Thanks a lot