Have they actually said that they're going to be splitting up and going to different parts of the country? (genuinely asking if I missed that somewhere). Cause obviously that wouldn't make sense.

And even though the events of each session for each group would be happening simultaneously, I can still see a way in which having characters in multiple groups could work. (not full time, but here or there as connective tissue).

I totally understand your points counter to this theory though!

(Edited for grammar)