From an Experts Exchange Question where the asker asked:
How do I block attachments from internal users to internal users but allow attachments to external users
Watch video Exchange 2016 Block Internal Attachments Only online without registration, duration hours minute second in high quality. This video was added by user David Johnson 08 August 2016, don't forget to share it with your friends and acquaintances, it has been viewed on our site 1,871 once and liked it 3 people.