This is going to sound crazy (and I've said it on lots of prev threads, so if you've been around for a while please forgive me the repetition ) but....
I have done 'retained reflexes therapy' to treat my DSs anxiety - and it has been absolutely amazing.
There have been loads of past threads on Retained Reflexes if you're interested to find out more...
But, basically, DS had retained the baby Moro Reflex (Startle Reflex). Which means everything that was startling him (loud noises etc) was flooding him with adrenalin, so he was permanently stressed and anxious.
We started it at the start of the summer holidays, and when he went back to school 6 weeks later school said "What have you done to him - he is so much better"
Now, it's not a quick fix. We have been doing exercises 10mins a day for 6 months now, and are about half way through the therapy.
And it's nothing like a support group which you asked about
But it is really worth investigating.