Wow, what a ride!! Congrats on finishing, it sounds like a tough day.
When you're done, you're done, there's totally no shame in getting a ride. Glad to hear everyone made it safe and sound - better than crashed in the literal or figurative sense.
I hadn't really rode with other people until our bike trip (just over a week ago now) and it was an interesting experience. I wish the 3 strong riders had stuck together through the windy portion, but sometimes you have to ride your own pace, and I'm too used to riding by myself and trying to maintain a consistent effort to be patient and wait for others. If you can find group rides that go about your pace, I think they are great learning experiences. I think some of the riders we were with got some good practice riding with a group.