Question for y'all that I haven't tracked down...
For my WoW guild, we leveraged Ventrilo phantoms in an Officer-only channel, combined with a secondary key-bind that triggered PTT for that other channel, regardless of what channel we were in.
In other words: A phantom in Channel B could be created, allowing you to listen into Channel B regardless of whatever channel you were currently occupying. PTT Key 1 would transmit to your current channel, where PTT Key 2 would transmit to Channel B.
Is there any way to do that in Mumble/Murmur?