I have a problem. My users are smarter than my transport rules. Let me explain in further detail. I have created transport rules on my Exchange 2007 SP1 server to disallow the sending of attachments to particular distribution groups. My users have figured out that they can manually select those specific users and then send the attachments that they want to send. I had a user in HR select all of the employees manually, close to 5000, and send her attachments out, which totaled 1 Meg x5000.
What I am trying to accomplish is rather simple. I would like to create a transport rule that will not let a user send attachments if the To Field is greater than 30 users. I know this has to be possible via power shell, as the predefined syntax/rules will not let you word it in such a way; however, I haven't found any type of syntax that supports this. Any direction would be great.