I have similar problems with my Wednesday group rides.
We have 1-2 _very_ strong riders. 2-5 riders that can hold their wheels but have no chance of attacking (I'm in this group). Another 3-5 riders who are strong but let the first 5-7 go up the road. And the rest of the pack (5-10) who get dropped almost immediately after the designated 'turn' point where attacks are allowed.
The problem we're having is that instead of having a few groups on the road to choose from or drop back to, the front 2-7 riders are so fast the rest of the group is starting to shortcut the route instead of chase. So if you (me) get popped, it becomes a 10-15 mile solo effort home. Not particularly fun, and usually if you're dropped after a few big efforts, not particularly useful as a training ride either.
There is usually post-ride beer available, so there is incentive to get back to the parking lot in a timely fashion (hence the short cutting). We've tried getting people to hold off until everyone returns, but that rarely happens.
I've considered adding in some chases, like the slowest group gets a head-start, then the middle group, then the fast guys and it's a chase. If done right the 'catch' should happen pretty close to the finish so everyone returns within 5ish minutes of each other. But so far this idea hasn't gotten any traction. The main complaint being "We don't want to wait around for 5 minutes before we get to chase".
I'm not sure there is a solution for non-officially-team-sanctioned rides where there is a defacto leader that everyone will listen to.