This suggestion is probably more relevant for a website administrator and associated staff...
Where a website has multiple sections each requiring a different username/password first display saved username/password details relevant to that page and then any other saved username/password details...
For Example: One could access said site's Forum, Email Ticketing, Database Management or System Management systems - each of these being available from a different URL (eg: http://example.com/forum, http://example.com/tickets, http://example.com/database and http://example.com/system) and the relevant username/password if different for each page...
The first prompted username/password that is shown should be based on the URL with all other saved username/password details shown following.