Menu Node Mailboxes will allow you to disconnect the caller after the message is played. Although the greeting does play 3 times before disconnecting.
Changing a Menu Node Mailbox Time Out Behavior
    Access the Administrator's Mailbox.
    Press [2] to edit or delete mailboxes.
    Press [2] for the Edit Mailbox menu.
    Enter the mailbox number to edit.
    Press [#] until you get to the Menu Node Time Out option. The system specifies the active Menu Node Time Out behavior:
    "Disconnect on menu mailbox time out is disabled" – callers are sent to the mailbox operator upon time out.
    "Disconnect on menu node time out is enabled" – callers are disconnected upon time out.
    To disconnect callers upon time out, press [1] (enable disconnect).
    To send callers to the mailbox operator upon time out, press [2] (disable disconnect).
        Note: The default is "Disconnect on menu mailbox time out is disabled".
    The system returns you to the mailbox.
The thing I always hated about the menu node mailbox is that you can't change the amount of times the greeting plays before going to timeout behaviour.