It depends. I had a coach who worked the Tuesday night ride into my program. He had me ride the route the opposite way at threshholdish and then grab the group as it was hitting the spot where it ramps up. That way I wasn't just warmed up, I was a bit fatigued. On the Saturday ride, I would be instructed to attack as much as possible, and basically try to drop myself. Then ride home at tempo.
Have a plan and make it productive rather than just ride around with a bunch of people.