No, I'm not the primary photographer, or at least I don't think so. I think my friend has asked a couple of us to take pictures, so that he does not need to spend the big bucks on for a pro. I hope we do ok.
Figuring out what you are going to do is more important the the choice of equipment. Try to get together with the other photographers before the wedding - if for no other reason than to recognize each other. Try to find out what formal/group photos are wanted, e.g., grandma and uncle Fred with the bride. Make a list and assign those to different photographers as much as possible. Get someone to round up the folks for the photos.
Failing all that, outside of the ceremony concentrate on getting photos of the folks attending. Even if they are just snapshots, they will be good memory prods years from now when they look at a photo of cousin Kathy and her (then) boyfriend.