Exchange Online Protection (EOP) Best Practices and Recommendations – Undocumented Features
New outbound spam options in protection portal include the ability to limit senders to [x] number of recipients per day. : r/Office365
New controls available to block automatic email forwarding! | Miss Tech
How to restrict sending to max 20 x recipients outbound for user mailboxes and allow more for systems sending out. · Issue #2729 · MicrosoftDocs/microsoft-365-docs · GitHub