How to mute one speaker in a group using the iOS app?

Prior to the recent app upgrade I was able to mute the speaker in one room of a group by simply clicking on the speaker icon for that room.  Since the upgrade, I've been unable to do that, and note that other users have identified this as a backward step in the updated app too.  The options now seem to be either to slide the volume to zero or to take the room out of the group.  The mute function was really useful if needing to quickly and temporarily mute the volume of one speaker e.g. to take a phone call.  The release notes for 80.02.04(iOS) say ‘introduced mute button on iOS’ but that seems to be for all the speakers in a group, so is there a way to mute individual speakers using the iOS app?  The Mac controller v.16.2 does still offer this feature.