Can SmarterMail work in a hybrid setup such as working as a backup for an Exchange Server? I currently have SM enterprise so I have the backup MX option in use so if the primary server is down such as rebooting then mail continues to flow to the backup MX as listed in DNS. The mail then flows into the primary mail server when it comes back up. If Exchange Server is added to the scenario, can SmarterMail function to help as alternative mail servers and forward the mail to the Exchange Server if it is rebooting or offline?