Add a block (blacklist) for specific destination addresses when using custom domains (Similar to block list on the spam filter, but for destination, not sender).

Why:

I use a catchall for my custom domain, so that I register everywhere with a different email and can easily track who's leaking my data.
The issue with that is that spam bots send emails to common addresses (like contact@domain) with phishing attempts.
It'd be good to have a way of blacklisting specific addresses on custom domains so that these emails don't even go through (ideally returning an error 550 5.1.1)