Yes, developing individual friendships from groups can be difficult. It took me years to properly understand this. It's quite possible to spend loads of time attending social groups but develop hardly any individual friendships from it. Your interactions with people can often remain within the group setting.

This is true of my improv group. I love being part of it, and I enjoy being around mostly the same group of funny people every week, but I can't imagine spending time with any of them outside of the improv group.

To develop a friendship with someone from a group requires something extra. There needs to be an extra reason to meet that person outside of the group. In the past, with Ramblers walking groups, it happened sometimes because I would offer to help co-lead a walk with someone, which meant meeting up with them individually to plan the walking route. Then a friendship develops.

With my outdoor mindfulness group, there was one older lady I developed a bit of a friendship with. That's partly because the ones she attended were usually in locations where not many other people turned up, so it was often just the two of us anyway. Then one day she fell off her bike and broke her wrist, so I offered to go round her house to keep her company while she couldn't go out and do much. I was often interested to hear about the issues she was having with her son, who is on the autistic spectrum (as well as having mental health problems).