I'd definitely recommend calling Groups for details, as I believe the info posted by steved5480 is incorrect.
Unless something has changed recently, group reservations are not charged to each individual flyer. The group coordinator makes a $50/person deposit in order to make the reservation. The fare is quoted by Groups, and is independent of any fare shown online. (Basically, all group members will have the same fare, unlike booking thru the website which often limits a particular fare to only 6-8 passengers.) Then a final payment is made for the full amount and names submitted. A week or so after that the deposit is refunded.
Groups bookings allow you to make name changes up to 72 hours prior to departure, and may (or may not) offer a small discount off the WGA fare (most likely it will be higher than the lowest but lower than the "average.") The trade-offs however are very, very long hold times when contacting the very, very understaffed Groups department (especially around schedule openings), and oddities like inability to add EarlyBird Check-In.
It's been a while since I've utilized Groups so please do contact them for the most current info. Good luck!