That's exactly it ! I don't know how to implement this "super-portal" ... I thought I could create a new portal and use it to store my pages, but then I have no way then to go to this portal ... Or maybe if I would declare a new set of url's (I will have a closer look at the request processor tomorrow) ?
Today here is where I am :
-> I have written pure static links ("/pvt/home", "/dotlrn/", etc) for most things,
-> I have a link to a page of the default portal to use a portlet (the "Courses" tab, to display the "Groups" portlet), but BTW the same page appears also in the My Space links in the submenu (which may confuse both future developpers and users : 2 links to 2 identical pages, one in a tab, the other in the submenu ...).
To fix the second problem, I only thought of making conditionnals (if page "Courses" then do nothing) but I think it's dreadfull. Anyway, I think that now things are clear so you'll be able to give me nice advice
As I said, I will post screenshots and (ugly) code tomorrow.