imap client see’s entire home directory

greetings well the imap server is working. how do i get the clients to only see one ~/Library/Mail folder ? i only want then to create mail folders inside this directory. I don't want to have to configure each client ( that would be a pain ) right now when i log in, user see's an Inbox the there are sub folders " his whole home dir " i don't wan't this to editable via their mail app. --tnx