You are the admin. You rely on the ISP connection and your infrastructure being available. It's doable but can be overkill. When it goes wrong/corrupted mailboxes it's a major pain. You have to be sure that you're not running a relay.
However, there's the alternative which is to use an 'admin' mail client to manage incoming mail with accounts on an external (normal) IMAP/SMTP service. You just run a suitable mail client in a logged in PC/Mac account on an always-on device. Then setup rules and accounts as needed, you can redirect elsewhere or move to other inboxes. You don't use this for everyday email access, it's like a Post Office.