2-h bike; this will likely be a ride I do weekly. There were 7 of us, one strong guy, 2 less-strong, and 4 women. Lisa, Jack, David (the strongest rider), and I were pretty much in front the whole time. David stayed back to ride with the others, and Lisa, Jack, and I stayed out ahead and rode the whole time together.
We rode on Long Lane, which has 7 rolling hills. It's a really good road to train on rollers. Our average was slowish (17-18 mph) and my HR was never over 80. I tried to keep a relatively high cadence until Long Lane, when I was just thinking about powering through some of the hills. Bad idea. I think that because I can't ever get my HR up, I have fewer lactic acid "matches" to burn; my matchbook goes empty before others' do. In that case, I really have to be careful not to power through too many hills; high cadence will be my friend, even if I might fall slightly behind. I was really trying to use my muscles like I've been practicing and definitely wasn't just hanging out for an easy ride.
Someday I'd really like to see how I do riding with a group with my HR higher (i.e. actually in my aerobic zone!). I'm going to have to figure something out. Hopefully running sprints will help me do at least one workout in my aerobic zone. Maybe when I go to spin class I'll watch my HR and see how it does then (if I can see the watch). If it stays in the actual aerobic zone, I might have to consider going to spin more often (I know it doesn't go up when I ride my trainer, even when I keep my cadence at 100+).