You are welcome in the group!! :)))) what do you mean? Did you have trouble posting or something? You are more than welcome here!
You don't have to join a group to participate on the forum. I've never officially joined any group on this website, as far as I can remember, but have been participating for a long time. And as you can see, your post is here. There might be more specific forums on here for the specific disorders you're referring to, however; most of us on the mental health forums, and there are several, are suffering from forms of anxiety and depression, not psychosis, and I'm sure there are forums on here that do focus on psychosis. But anyone can participate. All the best.