I agree that group riding is very different and it can be intimidating. I've rarely trained in groups and most of my etiquette/education has been on centuries and other rides.

I will say though that we did an impromptu TE ride in the Northwest and it went really well! We had a wide range of abilities and bikes but figured out a speed that would make everyone happy. Periodically someone would want to ride faster and that's ok, they would just circle back to meet up with us. The beautiful thing about so many abilities was that we could all learn from someone. It was mostly social but it was challenging too

Might be worth just getting a group of people and having a social ride. You might learn who is closer to your speed for regular/more difficult rides but it is so great to be pushed (if you're slower) or learn about group ride rules (if you're newer) and help with flat tires (if you're experienced in that).