[exim] Deny/accept based on MySQL user lookup

I have a passthru spam filter using mailscanner and Exim as the MTA's

I'm already looking up domains that the system will accept mail for by
populating the domainlist with:

domainlist local_domains = ${lookup mysql {SELECT DISTINCT domain FROM
domains WHERE Enabled = 1 and domain='${quote_mysql:$domain}'}}

and then futher down using

  require message = relay not permitted
           domains = +local_domains

Can I do this on a per address level as well? I get so much spam to
non-existent addresses that I'd like to stop at the front door.

Thanks, I'm a Newbie at Exim