Group two rooms

Because it isn’t necessary. There is already an “Everywhere” option when you tap the group icon.

The option to save a group is not really creating a permanent group. You are just creating a shortcut to group speakers. The “Everywhere” option would be the shortcut to group your two rooms.

Actually, I don’t think ‘everywhere’ shows up until you have at least three rooms in your system. 

This is correct.

And the reasoning remains the same.  There is no benefit in having an “Everywhere” option in a two-room system, when all you need to do to play on your whole system is a single tap, to add in the speaker that is currently not selected.  No functionality is lost.

For those who use Spotify app, can you see your saved groups as Spotify connect devices ?

HI. There is no possibility of Spotify or any other service using these named groups. As @GuitarSuperstar said, they are just shortcut button presses.in the Sonos app. There is simply no object for an external app to use 

It is really confusing because from Spotify app, I can create groups of two sonos speakers (in the spotify connect devices list). When doing it from my Beam 2, it redirects me to Sonos app on a hidden page where I can build the group but when doing it from my One SL it redirects me to the AppStore to download de Sonos S1 app !

What hidden page?

 Did you follow this: https://support.sonos.com/en-us/article/group-and-ungroup-rooms

When you play from the Spotify app you are not really using the Sonos system   You are using a bunch of Spotify Connect enabled speakers with the Sonos logo on them.

But it is still probably best to build the group in the Sonos app

Actually my need is to start playing music from spotify app directly into a group, without using the sonos app. I understand that it si not currently possible because it requires:

• Ability to create a group in a two rooms system
• Support of groups in spotify connect

thanks