Group Registrations - ability to sign up a "number" of volunteers in the group but still require each individual to register.

Our Org has quite a few "groups" that come and volunteer. Each weekend we need about 30 volunteers - and in that number we may have a "group" of 20. BUT we need each person to complete waivers - so we need all 20 to "sign up." It would be magical if someone could sign up a "group," but still require individuals to complete an application/profile/waiver. The existing problem is that if they just use the # and sign up 20 - it makes the math add up (ie: need 30 minus 20 group volunteers - 10 spots left for others to sign up), BUT we don't get waivers from those 20. IF they sign up as a group that needs the form filled out, then the 20 spots are not reserved and until they do - it still shows 30 openings, making it very possible to get "over-booked" by volunteers that want to come. Often groups wait till the last minute to sign their docs.