The only secret group that I am in is for an organization which is, in turn, a secret. I can't imagine why you'd want a truly secret group otherwise. Not just

The only secret group that I am in is for an organization which is, in turn, a secret. I can't imagine why you'd want a truly secret group otherwise. Not just closed, where non-members can't see the content, but secret, where non-members don't know the group exists.