If you block a domain in webmail you manually have to delete it or move it to junk.

A nice option would be that a block automatically either deletes it or move it to junk email.

And maybe a global spam list on the server thats updated everytime somebody adds a block sender in webmail or outlook and add it to the SMTP block/EHLO block so nothing from that domain gets through afterwards......

And the domains on the server is whitelisted automatically so no one can add a hosted domain to a blacklist.