I believe that if you have two equally fit people and one is on a heavier bike, that person will be slower, especially on hills, than the person on the lighter bike. If being slower on hills bothers you, and it seems to, and you aren't in a position to look at new, lighter weight bikes, a new wheelset can make a significant difference. If you do a search on this forum you can find many threads on that topic. The other possible solution is to train so much you are stronger than the other riders

I was fortunate enough to be able to buy a new carbon bike late last year. I am faster than I was, but one of my riding friends on an entry level all aluminum bike is still just as fast or faster because she is stronger than I am. I ride just as much or more, but she has always been very athletic and seems to have more muscle mass than I do, at least that is my story, and I'm sticking to it