This is the perfect application for Mute Groups, added in v1.2 firmware.
You can have up to four. Go to Config → Control & Network → Mute Groups and assign input channels or outputs to the mute group.
There’s then an extra tab on the processing and fader pages to access the mute groups, or you can set them up on a custom layer, or assign them to a soft key.
The only thing that you might discover is that things can’t belong to more than one mute group, so you’d need a mute group for the aux outputs and another for the Main LR.