Why can't I group two rooms?

Because you already have a default speaker group containing your two rooms.  It’s called “Everywhere”.

How do I access that from a convenient button? When I’m playing music on Spotify, either using the Spotify app, or using a voice command to Google Assistant, I then have to manually go into the Sonos app to play it in the other room too. 

Creating a speaker group doesn’t mean you can access it via Google or Spotify.  It’s simply a quick way to group things like “Upstairs” or “Downstairs” without having to individually click on each room.  You still need to go to the Sonos app and click the Group button.  Once you do that, your saved groups are at the top of the grouping screen.  

So where is the Everywhere group, please?

I believe (but can’t personally confirm) that the ‘everywhere’ group only appears if you have more than two rooms in your system. If you only have two rooms, I believe you only have the option to select the two rooms. 

Not having only 2 rooms, I wasn’t aware of the Everywhere room not appearing for systems with only 2 rooms. 

It wouldn’t save any clicks anyway, there’s no difference between hitting the “Everywhere” button and checking the 2nd room, both are a single click.  And the only reason for saved groups is to save clicks.

Yea, I’ve got the same problem, too many rooms. But thought perhaps that might be why the OP couldn’t find the ‘everywhere’ selection. 

It sounds like I need to wait for the Google integration to catch up to the Alexa integration, and allow groups of Sonos speakers

Even that isn’t great.  Alexa allows you to initiate play to a group, but there is no on-the-fly grouping and ungrouping of rooms like Sonos is able to do.  If you want to change music from one room/group to another with Alexa, the music has to stop, then restart, and it doesn’t restart where it left off.  

Hi,

I was just about to post on same subject - I am in the same position as OP and am feeling mystified by it as I’ve not knowingly changed anything. It seems to be a new development, and to be interfering with my ability to play off AirPlay, as my old Play:1 has dropped off the AirPlay group and I can’t figure out how to pair it back up again. Very frustrated as I obviously need the piggybacking from my Play:One to make AirPlay work on the older speaker, and it was working just fine.

Screenshot below. To note that there’s no reference anywhere to an “everything” group, just the old two room setup I created in the old app, where I definitely could edit these settings as needed. It all still works from the Sonos app, but I can’t use that for Apple Podcasts and its interface with iTunes isn’t really fit for purpose, so I need AirPlay.