I have a long room in which I have two Play:1s set up as a stereo pair.  I’d like to put another Play 1 in the room so that there is a L-R-L setup, with the R in the middle of the room.  That way I have stereo sound on the left side of the room, and stereo sound on the right as well (albeit reversed).  

Is there a way to add a Play:1 as a left-only speaker?  Whenever I set it up, it is only available as mono.