i think the real thing is to get to the bottom of this cycling thing you had going on instead of putting it by the wayside.

you need to ask yourself what you want out of the sport. recreational or intense? fun or training? you seem to want part of both but it can't work that way.

if you want to be a recreational cyclist then go for a ride by yourself or others at a faster pace every now and then to feed that craving and keep yourself sane on the bike when you're in your slower rides.

if you want to be a more serious cyclist then don't settle for riding with people slower than you. maybe on recovery rides or longer weekend rides you can go with them. if you want to get better then you have to ride with people who are faster/better than you otherwise you won't reach as high a potential, if at all.

if you want to be a recreational cyclist then you need to change your mentality and frustration about riding slower. teach yourself and remind yourself that you enjoy being on the bike and keep it at that.

if you want to be more serious on the bike then ride by yourself more. it is possible. that way you can't complain about the group's pace (slow or fast) and rely on yourself to get whatever you want out of each ride.

...just some food for thought.