hi, is it possible to create a menu (static) that will change in a submenu on click...

for example... my mainmenu has 3 entries... 1.home 2.downloads 3.links...

now when i choose links i want that the link-site appears in the center and that my mainmenu changes in 1.main-links 2.misc-links 3.old-links 4.back

or if its not possible that a 2nd (sub)menu appears in the right block with these new menu entries...

can anyone help me ?