This is a question I have struggled with for a long time. I have a structured training plan, but I enjoy my 3 group rides every week. I have a hard time getting in the workouts I am supposed to riding these 3 group rides every week. I am a coach so I know what I am supposed to do, but that doesn't mean I always do what I should. As my parents used to say "Don't do as I do; do as I say." :-)
The problem with group rides is that the are unstructured and impossible to accomplish the specific tasks that your training plan calls for. Of course, there are some exceptions like when the group ride is a recovery ride and you need that. Also, there are "training" rides where a group of riders get together and agree on a specific purpose for the ride that agrees with their training plans. Training rides have structure while group rides do not.
For me, I need to make a change next year. While I will continue to do my 70 mile Saturday Club Ride, I will need to think about what I will do on Tuesdays and Thursdays. I really want next year to be a break through season for me, so I need to make some changes.
You may ask, why I am thinking about this at the end of the season. I read an article on Pez Cycling News that talked about this very subject. That article can be found here:
Let me know what you think about this topic.