During our last 3 group rides I found myself opting for staying with the B group (which has become stronger this year), rather than trying to keep up with A guys and suffer the whole ride with repeated near-vomiting-inducing efforts.

I find myself pulling a bit longer in the B-group. Every once in while, one of the regulars is having a bad day or there is someone new just trying to keep up, and they sit at the back without taking their turn. Everybody including myself is OK with it, but if they drop, we don't wait.