Hey DJC
I took a bad tumble myself two weeks ago on what must have been the worst day on the bike I had since I was 11.... 3 punctures and a snapped chain.. The snapped chain caused the fall but I was lucky I didnt damage too much of myself. The chain snap happened as I was in Pfaffikon, so I could at least get the train back home to Zug... otherwise I was screwed...
As for group rides, I agree that the respective fitness of the riders will determine how good the group is... but to be honest groups can always go much quicker than a person on their own. i dont think I can ride that fast, but I am trying... and to be homest coasting along with a group at 30kmph and having a chat is the best fun to me - it makes the time and the miles go faster and fitness can be incrementally improved...
Even though I am aiming for the marmotte, I am not a climber by any stretch of the imagination. I am about 82kg, 181cm and the hills tear up my lungs... but I'm getting better :-)

Ed.