How nested group works

Emmanuel, please tell me, following settings are correct?

comando top - level 3 - nested group:none
comando ts brasov - level 2: nested group: comando top
comando ts bucuresti - level 2: nested group: comando top
...(other more 5 subgroups)

If yes, then i have a problem because i'm logged in as comando top user and i see 7 links instead of one

In the structure you show me commando top (which is nested in every other group) inherits the permissions of all other groups.
Thus commando top can see all the links the other can see.
If commando top must have LESS permission and see LESS links than the other group, your structure must be reversed.
Cheers,
Emmanuel.