Yes and no. You can add things to the Exim ACL directly (/ etc / exim.conf) but it is very limited in what you can do. Here's a sample rule from the ACL:
deny
senders = *@nyc.gov : *@ups.com
message = No Such User Here
log_message = More fake speeding tickets of UPS receipts!
This blocks those stupid fake emails from the New York Police and UPS that have viruses attached. NYPD does NOT email speeding tickets and UPS doesn't send emails with viruses attached. Actually UPS never has your email address so why would they be sending you a receipt?? Long story short ACL is good for rejecting based on limited info but not so hot if you're filtering key words.