The IOS tri club has had training rides leading up to Raleigh 70.3 the past two years. Also nice group of folks. They do trainer rides during the winter. I don't see any outdoor group rides on their calendar yet, but keep a watch on this page. https://iostriclub.com/IOSTC_Club_Calendar.php
Tri life in Raleigh I think also has some group rides on Tuesday evenings. Looks like they are doing trainer rides for winter. http://www.trilife.co/event-calendar.html
If it doesn't have to be a tri group, consider a cycling group. Depending on where you are, you could go with the gyros, cycling spoken here, spoke cycles... There are quite a few weeks n the area.
Riding Zen means nothing more than being keenly aware of your surroundings and in control of your emotional state at all times. It also means riding safe and riding smart.
The most valuable thing you can do for your endurance training is to schedule a weekly 2-4hr long ride from now until the end of time. Simply make this “what you do” every Saturday or Sunday morning.