Best answer by PPaulp
The added benefit is that you can prefix defferent volumes for each speak whn it becomes a group. This is great for mivies etc.
Download the Yonomi app (free) and set up a command list that plays 5 seconds of silence on all of teh speakers that you want to group. It will then group all the speakers together after the silence finishes. Its important to add the command ‘set repeat to off’ and ‘set shuffle to off’ for each speaker , after the silence (this prevents Sonos from moving to the next song in your playlist library).
FYI, you can find short recordings of silence on line with just a google search. You can also add it to Sonos as a ‘favourite’ by uploading the silence to soundcloud and synching your Sonos and sound cloud account.