Since you mention a large group and snorkeling, I suggest you take a looks at Dive & Trek Anilao. It's definitely an older property, but good food and Amazing(!) snorkeling on their house reef for the non-divers and divers alike. They're very good at accommodating large groups (Miss Earth Pageant group goes there annually).
Edit: I suspect that D&T may be able to work a deal or group discount with as many people as you've mentioned. I would say it's definitely worth an email or call.
Also, they're Diver Rate includes unlimited air fills for shore dives. Boat Dives and DMs are on a per person per dive basis, divided among participants on the dive(s).
For full disclosure, I am not associated with them in any capacity, but go there very frequently with my dive group. In fact, I'll be there overnight tomorrow. If there is anything I can try to do for you, please feel free to PM me.