Back in the day, group rides had a boss who would keep things going correctly and not be shy about it. The group rides in my area are a cluster chuck.

A weekend endurance ride to the cafe and back should not have showoffs jamming every hill ruining the training effect for everyone and then slinking back sucking wheels to ambush on the next hill or worse, some undefined Strava segment lurking up the road. Who really cares if someone sits a little long on the front on a long endurance ride? OTOH, a fast training ride should have more defined pace and pulls. When I was on a team, our training pace was fairly set but what varied is length of pulls. Schmucks like me might just pull thru and be there for 20 seconds whereas the very strong captain could take 2-3 minutes up there (single paceline) and the other riders 40-60 seconds.