We have been in your situation with 8 of us on a family cruise on Constellation. We were in a CS suite and the others were balcony cabins. First, it was very hard for us to get everybody together for dinner in the MDR as our group had different tours, schedules, choices. Herding cats. Maybe your family will be different. But getting a larger table in the MDR was no problem once on board - they were very accommodating.
We were also able to call the shoreside suite concierge to arrange Specialty dining for our group in advance. You can most certainly do this if you are in a PH suite.
We were able to arrange for the 8 of us to have dinner in Luminae a couple of times. It was free for us but $30 pp for the non-suite guests. Much less expensive actually than a Specialty restaurant and the group loved it! But you need to arrange this with the Luminae Maître 'D once on board and probably for a less busy time after 8 PM. Your account will be charged - but if important you can settle with your group in other ways. You can also take all or some of them for breakfast ($10 pp) or lunch on sea days ($20 pp). Breakfast was mix and match with our group since our family had different sleep schedules.
My best advice is to just enjoy the experience and not try to control the group too much.