[Exim] antivirus.exim allow domain

Good day,

One of my clients is an antivirus developer and he needs to receive
"dangerous" files from his customers in order to analyse them.
The problem is that I have no idea how to allow this files to pass
through only to his email accounts and not for all the domains hosted on
my server.

Any help will be much appreciated,

Regards,

Marius Herea