This feature is on my wishlist too ~> more frontend-groups (access-level); not in every case with the permission to add/edit/... articels. I mean permission to various areas. Background is a website for a company I have to "create" with areas for customers, members, the lower and higher management, ...
Your solution is not an access restricted solution.
That's right >> only authorized user can see
But in case I know the link I can type it into my browserline ... and I'll see what I want