Jane Stafford Textiles or the School of Weaving do not have any official Facebook weaving groups. We don't monitor or oversee any that may be out there. This forum here on School of Weaving is a pretty cool place to hang out :) You could also check out Ravelry's 'Weave with Jane Stafford'. There are lots of fun chats, help, and weaving projects there too.
That all said, there are FB groups out there that folks can join that are not run by us. We haven't looked at them all so unclear about the one you are talking about but we hope you find one that works for you. JST does have an official FB page and an Instagram page in case you want to follow us there. Hope this helps!