keeping email from expired account visible
Recently we eliminated a domain that we have had since 1997. We don't think it's a good idea to disable the email accounts associated with the domain in Apple Mail, because then thousands of past emails disappear from our Apple Mail mailboxes. Yet it's inefficient to keep the accounts fully enabled so that Mail tries to connect to them for new mail. Is there a way to keep emails from an old account visible, but stop Mail from trying to connect to the account? Apple, if you see this and there is no such way, wouldn't this be a worthwhile feature to add to future versions of Mail?
MacBook Pro, OS X Mountain Lion (10.8.2)