email: how to configure postfix / dovecot settings to reject certain mail for certain users / accounts

I would like to reject the email of certain users or if it contains certain strings or if the title matches something for certain users.

I'm in a multi-domain environment.

it's possible? Unfortunately, this (how to configure the postfix / dovecot configuration to reject certain mail) does not fit my needs because it suggests its use header_checks Y body_checks to block on certain chains. I could also use smtpd_sender_restrictions to block emails from certain users but do not for certain users.