I'm receiving an excessive amount of spam 1000+ messages a day. They are all supposedly coming from my domain name, but I'm the only user so I'm confident it's not the case.

The emails are usually myname1@mydomain.com, myname2@mydomain.com etc etc.

Zoho is doing a great job at filtering over 99% into my Spam folder, but I wondered if there was a way of permanently deleting any emails that come from my domain, except for known mailboxes. I only have about 6 addresses I actually use so could add this manually.

So basically permanently delete any emails sent to mydomain.com if the sender is mydomain.com, unless it is knownmailbox@mydomain.com or inbox@mydomain.com etc.