Our weekday training rides, which are sponsored by the club and do have a ride leader, are marked so you can ride at whatever pace you want, although the expectation is that you stay with the group (there are actually at least two groups at most rides, one faster than the other). If you pull ahead or get dropped, you're on our own. The ride leaders will sweep the course if someone doesn't return to the parking lot within a reasonable time. There are multiple training rides, however, around town on any given day. Some are more "maternalistic/paternalistic" than others. The more they cater to the racers in the club, the less likely that anyone will care if you stay with the group.
When I ride more informally with a group of friends, we stick together. I've never known anyone to sprint off and I've never known us not to slow down if somebody starts to struggle.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher