[exim] 'super' imap user

I wish I knew if there was a term for this:

An imap account that virtualises all the users as subfolders of the
'super' account. e.g.

Stephen
    - Inbox
    - Sent
    - Trash

Bob
    - Inbox
    ....

'super'
    -Stephen 
        -Inbox
        ...
    -Bob
        -Inbox
        ...

Is it possible to do such a configuration in exim?

Cheers

Stephen