Set them up as two rooms, and then group them? 

“Group” is apparently only an option for 3 or more rooms.  I only have 2 rooms but I’d prefer not to stereo pair the speakers

That’s only for defining a saved group to use as a ‘macro’ when selecting rooms to group. With just two rooms the ‘Everywhere’ button suffices. 

Here’s what you need: https://support.sonos.com/en-gb/article/group-and-ungroup-rooms

I am not able to get to the “Everywhere” button because the “Groups” option is greyed out.  When I try to click on it on the S2 app, I continue to get the error message : “This feature is available on systems with three or more rooms”.  Is there another way to get to the “Everywhere” option ?

I was able to group the two speakers manually using the buttons on the speaker itself. Thanks

The ‘Everywhere’ button is on the grouping popup, as displayed top right in the article I linked. 

Like I say, the saved groups option in Settings is irrelevant unless one has more than two rooms. 

The Groups setting is for creating Groups, not utilizing them, which is why it is greyed out for systems that only have two rooms.  This is how you Group:

Thanks for the help !