I started my private flying in a group, and benefitted from the experience of other people around me (mind you, I think some others probably also benefited from having somebody around who'd done their PPL recently enough that they could still remember what was in the exams). That's just a caution that setting up with other recently qualified students you might find that collectively you need to look for guidance outside sometimes.
For either sole ownership, or if you are looking to set up a new group, do consider some of the smaller PFA types. There are some nice machines there, which (particularly if you don't mind putting some work in yourselves) will save you a fortune compared to a CofA aircraft. You can't be instructed on a group-owned permit (PFA) aeroplane, but that's the only real limitation (apart from being limited to day-VMC which doesn't worry many PPLs) and it also allows access to PFA's coaching scheme for checkouts and BFRs.
G