How can I block outbound to a specific domain with exceptions

The boss says that nobody should be e-mailing to hotmail.com except
for a chosen few that he will define. He's the boss...

How can I configure Sendmail v8 to reject or bounce all messages
addressed to *@hotmail.com unless the sender is in the good ol' boys
list? Pseudo-code like:


define chosenFew {joe@gmail.com, fred@gmail.com, sam@gmail.com}

if recipient = *@hotmail.com and sender <> chosenFew then
reject, bounce, trash message
else
send it
end if


I'm a Sendmail configuration noob, so pointing me to some chapter and
verse isn't going to be much help. Pointing to (or posting) a real
example or snippit of a config file would be perfect.

Thanks.

--
Sal