We are wanting to restrict receival of email to users in certain OUs across our enterprise. The idea is to allow users to receive certain emails from certain security groups and disallow emails from all external mail address. This can be done manually via the AD account / delivery restriction / "only from" however needs to be implemented over a thousand mailboxes. Can this be done via some sort of script. We do not run any mail filtering third party software. We run Exchange 2003 across the enterprise. thanks

You can also use smtp connectors to set restrictions.