I'm in the middle and it sux

Find another club! 

Or see if some of Cs are ready to move up, and find some Bs that aren't A wannabes, and lead another group.  Once the local clubs in my area has a B ride, and B+ ride. They have done a pretty good job of defining the average speed of the different groups.  The ride leaders are good about trying to keep the ride within the standards defined for that particular level of riding.

Even though we can't draft in our races there's a tremendous benefit to training in a group with riders that are a little stronger then you.  If you can sit in with those guys you get stronger.  One thing that I try to do when riding with agroup taht's better then me is to stay closer to the front.  That way if I start losing it, I can try to jump on another wheel.

Yeah, I've rode a couple times with people from my gym, all triathletes, but they too set 25 mph pacelines and go 80+ miles.  Both beyond me mileage and speedwise.  I like riding with them, but have resigned myself to riding alone and/or finding another group.

  Going that far that fast and trying to keep up isn't good for my training. 

Chris

Yes it is easier to sit in and be taken along in the draft.  However there is a benefit to sitting in with riders who are a little faster then you.  On your own maybe your average is 19 MPH, but in a somewhat faster group you may be able to average 22 MPH.  Your muscles get used to that faster pace, and your average pace on your own will increase.

My average pace in Olympic distance races improved tremendously from riding in a group with faster riders.  I've posted faster bike splits in my late 40s and early 50s then I did when I was in my late 30s and early 40s.  Most of this I credit to group riding.

Sometimes I get dropped, but I keep my pace up and I treat it like a time trial.

Wrong. Drafting does not make necessarily make it easier. Done right, cycling can be faster to ride in a pace line. That doesn't mean you're slacking or putting forth less effort or pedaling at a lower heart rate. You may be putting forth less effort per MPH, but achieving great speed for your effort.

Team cycling uses a strategy where the "star" is protected and saved for the end of the leg. That doesn't have to take place in a noncompetitive group training ride, where riders take equal time "pulling" the pace line.

Agreed there is no benefit in the original poster's situation, but that was not a group ride. That was him trying to keep up with a group riding above his ability. You guys are dimissing group riding as having NO BENEFIT and that is, again, wrong.

I'll throw my 2 cents in...form your own mini group.  We don't have A, B and C riders in our club but when we have a large enough group we'll almost always end up splitting into 2 smaller groups to accomodate more people.  By mutual agreement at some point the "breakaway" group just keeps on going, and the slower group does thier own speed.   Do you think if you suggested something like that it would work? 

The best thing about riding with a group (particularly one that's faster than you are) is that the group will push you to a higher level of cycling than you could achieve on your own. Drafting and pacelining, in addition to providing a set of bike-handliong skills that triathletes are infamous for not having, allows you to have intervals of riding at a pace you could not maintain on your own, then being able to sit in the pack and recover before doing it again. This kind of riding will make you faster.

Now, if you are getting dropped by the group after 5 miles this week, make it your goal to hang on for 6 miles next week, 8 miles the week after.....and so on. Work on bringing yourself up to their level.....and dropping them like a bad habit next year (or sooner) Yep, it's going to hurt, but you'll come out the other side a whole lot stronger.

Back when I first started road biking with any regularity, the group I rode with usually spat me out the back on the first hill, and I'd see them at the finish. Gradually though, I got stronger due to being pushed by the group and driven by my fragile, and now bruised, ego. These days, I can keep up on the hills, and drop the lot of them on the flats.

As a direct result of this process, my solo bike speed has greatly increased (from a 16-17 mph average to a 18-19 or better avg with the same 80-100 ft/ mi average climb rate around here).

Stick it out. You'll be glad you did.