[Exim] Max mail size per user?

I can set the maximum mail size with message_size_limit, but is there a way
to disable it for a specific user or group of users?
Better yet, a database of From emails and associated max allowable mail
size to override the default.

Anyone heard of such a thing?

Thanks,
Marc
--
Microsoft is to software what McDonalds is to gourmet cooking

Home page: http://marc.merlins.org/ (friendly to non IE browsers)
Finger marc_f@??? for PGP key and other contact information