The question reminds me of ISP Email systems from over 15 years ago - SPAM fighting would involve typing many pages full of text strings 😁 !
As CP MTA uses postfix, you could also do this in postfix using Postfix Configuration Parameter:
body_checks(default: empty)
Optional lookup tables for content inspection as specified in the body_checks(5)manual page.
Note: with Postfix versions before 2.0, these rules inspect all content after the primary message headers.
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