Hi Neal,
I have 3 Sonos speakers, 2 set up as a stereo pair in one room (named Living Room) and a single in my office (named Office).
You first need to understand that when the B2 plays to a Sonos speaker it is NOT sending music DIRECTLY to that speaker. It is sending the Music to the Sonos System. It is the Sonos system that sends the music to the specified speaker.
You can see this happening if you have your Sonos App open along side the Brennan Web UI as you do things on the Brennan.
Thus,
Using the Brennan Web UI, I can select "Office", then start playing a playlist (Red on my case) and the B2 will then play that playlist on my Office speaker.
And in the Sonos App you will see
Thus you can see that as the MUSIC files of content of the Brennan Playlist (On the Brennan a playlist is a TEXT files pointing to music on the Brennan HDD) have been uploaded to the Sonos System,.
Now if you go into the Sonos App and select random there (I have ringed the button above), the Sonos System will play the files in the list in random order.
Anyhow - that how I do it - The Brennan Web UI random button does NOT seem to change the State of the Sonos App random button! (Not sure if this a BUG or there is some technical reason why it can't do this)
Fred