Master Volume - auto un-mute

I use Roon personally and love it and am now considering to implement it for my company for our audio demo system comprising of multiple zones and/or speaker types.

Everything looks absolutely ideal except for one big sticking my point - the Master Volume control for grouped zones. Not having a Master Volume slider is the minor bugbear. The big issue is that as soon as you use the Master Volume adjustment it un-mutes all the zones. Is there any way to stop this?

The reason is that we want to be able to mute all zones except for say two (e.g. one zone a pair of satellite speakers and the other zone a subwoofer matching the satellites). Muting/un-muting allows us to demo with and without the sun for example. We then want to use the Master Volume control to adjust the volume of just those two zones without un-muting all the other zones.

I would love to see that feature as well