The Premium page lists what each package gets, as well as a list of features included in all Premium packages.
Membership Perks

I guess my main question is if I get a Gold Membership could I start a group for my local chess club?

One group, yes. Gold is limited I think to starting one group (or a small number such as three groups, I forget which). General info:
http://www.chess.com/membership?c=navbar
sftac
ps. I also believe there's a one-time refund if you're not happy with your Premium membership. If you hang about long enough (12 months?), you'll likely receive a free trial (10 days?) of Diamond membership.
Hello All, I was thinking of becomeing a premium member here at Chess.com and I was wondering if any who are already members could tell me if the added perks at the bottom including no ads, groups and teams, computer workout, vacation time, etc. were included in even the gold member's package?