We are planning on rolling out e-mail access to students within a high school environment.To stop students using the system as an IM service during class we don't want them to be able to email each other, we also don't want them to be able to email out of the organisation. However, there will be some students who will be granted external mail (Business studies students) and there will be some who are able to email other students (Student Council Members).I know I can stop mail exiting the organisation using a transport rule, and I realise I can use Message Delivery Restrictions within Mail Flow settings to stop students from receiving mail from other students, but I see a few flaws in this currently.Mail Flow Settings seem to have to be set per user, although I suppose a powershell script could be written.When a member joins the school council, every other student will need to have the new members name removed from their restricted list, again, I suppose this is where powershell comes in.Am I missing something obvious, is there a more elegant way to do it?Alex

Hi Alex, I do think that the Transport Rule is the easiest way to configure the mail flow. You can configure Rule like below: To stop students to send emails to external user except Business studies students Group Conditions: From users Inside the organization and sent to users outside the organization Actions: Send Delivery not authorized message refused to sender with 5.7.1 Exceptions: Except when the message is from member of Business studies students Group To stop students to send emails to internal users except Student Council Group Conditions: From users Inside the organization and sent to users inside the organization Actions: Send Delivery not authorized message refused to sender with 5.7.1 Exceptions: Except when the message is from member of Student Council Group You need to create two groups for Business studies students and Student Council members Mike

Cheers Mike!I hadn't seen that you had replied! That's perfect