If you were to use a straight IMAP client (Outlook, Thunderbird, Evolution, etc) you could simply configure multiple accounts for those users. It would then be up to the user to maintain which mailbox they were looking at.
Another possible alternative would be to use the CLI command zmmailbox to add a mount point and permissions for each user that you want to add, but that could easily turn into an administration nightmare.
Personally, for situations like this I have used distribution lists along with filters and made sure that any mail sent on behalf of the distribution list also CC's the list.
Robert |