I don't know how modern schools are organized. I don't belong to any. I do know, however, that you don't need an institution to become gnostic. Gnostic knowledge is suppose to be personal insight into the order of the universe. Since it is supposed to be personal knowledge, you can't learn anything from a school other than all of the inadequacies of the teachers. It's not a conforming belief, its interpretation is supposed to be spiritual insight into the soul.