Those trails look amazing! I'd say give the group rides a couple of goes for the social side, make a few more friends and then arrange to go for your own rides with a handful you get on the best with, and who would also be up for the peaceful ride through nature kind of vibe.
Thanks man - yes the trails in the Phuket mountains are really special. many of them are generations old and were here long before tourism arrived in the early 70s. Good advice by the way - put these hash bikers through a careful selection process!