[CentOS] Sendmail - block mail based on recipient address?

Mon Oct 25 14:44:07 UTC 2010
Sean Carolan <scarolan at gmail.com>

Maybe someone can help me sort this out.  I want to block outbound
mail from my network based upon the recipient address.  Internal
servers should still be allowed to send emails, but not to a few
specific addresses.  I've tried creating some rules in
/etc/mail/access but to no avail.  Is it possible to do this?