Question regarding whitelisting part of a domain

[Mike Tremaine]

This is a strange one and I'm not sure how to do it off the top of my head. I've got a domain that wants to try out mailscanner BUT they only want a few [6] addresses filtered. The rest they want to let through untouched. [Yes I know but it's a waste of oxygen to argue sometimes]. Without getting a full list of valid email addresses can anyone think of a clever way to whitelist the domain EXCEPT for the the 6. I don't think the rulesets allow for negation in the matching.... I also assume the biggest rule win so

To: thing1 at somedomain.com	no
To: *@somedomain.com	 	yes

Would not work in the spam.whitelist.rules

-Mike Tremaine