Our site is a membership site, everyone has to sign in. The forum is critical to site but it is not the central feature. The requirement is that when someone signs in to our site with our custom login system, we need to log them into XF at the same time. Related requirement: when someone joins our site, they can join by buying into any one of 40 products we have. Each product has its own private forum, with a user group that has access. We need to be able to add people to user groups when they buy products and remove them if they cancel or fall behind on payments. I looked for information on how to do this, but am not finding what I need. is there any direction or guide for this? Any information on this would be extremely much appreciated.