Best answer by ratty
No and no.
A group is a temporary arrangement where a number of 'rooms' are joined together to play in sync. Each room plays the same content.
What you're asking for is a 'bonded' setup, where a number of players are all subsumed into a single 'room' and each plays a different channel or different frequencies. You can not bond using a Play:5 as centre. The only players which support a home theatre bonded setup are Playbar, Playbase and Beam. In those cases the main player outputs L/C/R as 3.0, optionally with the addition of surrounds (+2.0) and/or Sub (+0.1).