I have been using the plugin BuddyPress Private Community on all my sites and sites I create for clients where I want privacy.
I know you have something similar, but, it does not work the same.
This plugin requires some manual changes to work right, but, it works phenomenally well.
The plugin has not been worked on in years, but, it still works. I think if you took over this plugin, or came out with something very similar, eliminating the need for the manual changes, you will make a lot of money from this because there is a deficit in this functionality and there is a high demand for it, and, online searches really come up with nothing comparable.
If you try to go to http://blogurp.com/members you will see what happens with this plugin in action.