"Who don't feel that they can join any local groups"

There's your problem. Fix that.

If there aren't any local groups then help create one. If there are, go along, meet some people, see what works for you, join a different one if you didn't like the first one, keep going until you've found your people.

If you feel like you can't go to a group then create a support group for people who feel like they can't go to groups. Or go online and find the virtual space for people like you and then travel to see those people (or invite them to see you).

But there is no fix for you having to socialise if you're lonely. You're going to have to find a way in.