I've fouund the "user spécific content" plugin whose not so bad.. It display a wp box at the bottom of the post editor page where you can select who can see the post.
Great but in order to save some thousand clicks, i would use the inversed function plugin.
A box in the post editor....
-> a checkbox to hide the post to the non-logged in users (private).
-> several checkbox (as much as subscriber users) to select who can't have to see this post, or just a field to enter (separate with commas) the name of the no-authorized users)
For more explainations : I have 3 post A, B, C.
(not logged in...) Everyone can see A, great noone can see B & C.
(once logged in...) Mark can see A & B but can't see C.
(once logged in...) Helen can see A & C but not B.
I've found "role-scope" plugin, but it's a real huge machine for this !
sorry for my marvelous english, I wish you the best,