menus with visibility options

Hi,
I would be nice to have the possibility to change the sidenav menus with context.
Here's an example.
I'm logged in, the first menu appears
-home
-client search
when I choose a client, my menu changes:
-home
-admin (client administration)
-orders
We could create all menu-items in the first place but change the visibility of some of them with context.
Thanks
Jean Vandromme