There's no shame at riding in the back of a group if you can't pull.
I regularly do this on Wednesday group rides where 1/2/3's, State Champions, and even an Olympic Gold medalist (speed skating) are regulars.
On the way out (usually moderate pace into the wind) I take my turns pulling. On the way back, I suck wheel for as long as I can hold on.
It seemed like every month I could hang a little bit longer, last few rides (before I got sick) I have been able to hold on all the way back to the parking lot.

If I wasn't 'allowed' to even join the group because I couldn't pull, I'd be sitting on my couch 30+ lbs overweight. Keeping up with that group (and shortly thereafter signing up for races) was the motivation to keep me on the bike.

For the record, that Olympic Gold Medalist has only intermediate bike handling skills, but HOLY CRAP does he have a sprint. And his thighs look like Chris Hoy.