Permission and home album

Hi,

Let's imagine following gallery hierarchy:
root album
- album 1
- Album 1-1
- Album 1-2
- album 2
- Album 2-1
- Album 2-2

If I give to a user (user1) read access to album "Album 1-1", and if he uses the global URL to reach the gallery he has an error.
Then I provided him read access to root album but not to album 1 (only yo album 1-1).
My issue is:
when he logs in he is in root album and gallery says that this album is empty. Normal since he doesn't have read access to
album 1 and album 2.
However with the tree navigation I installed, he can see in the right panel album 1-1 directly attached to root album

Is there any way to display Album 1-1 under root album ?

1 workaround is by giving read access to album 1 but as my hierarchy is pretty complex, if each time Iwant to provide access to some specific albums I have to provide read access to all intermediate albums aswell it is going to be a nightmare in the permission.

I tried by using tags but if you try to access to a tags album
www.xxxx/com/tag/user1 and you are not already logged, gallery return an error without asking you to authenticate.

What is the best way to provide access to some albums without providing explicit link to each albums ?

tks

Xavier