There is not much I can offer in the way of advice that was not already stated. If you want to get better on your bike, you have to bike. It does suck being in the back, especially if people are waiting for you.

As I have stated many times before on this forum, my regular group of riding partners is all men, DH included. I can climb better than some, and they are all faster than I am descending. They are fast. So in my learining curve, I had to make a decision whether or not I was going to ride with them or not. I chose to stick with them. There are days I feel beat up chasing them, but overall, I am a better, faster rider for having hung with them.

So if it is important to you, that perhaps take a clinic, and stick with it. Riding with faster riders will make you faster over time, and then you will not be in the back.

Good Luck,
Ruth