Exchange 365 Mail Flow Rule

[Grendon_Tech]

I want to implement a mail flow rule to prevent pupil users from sending emails outside or receiving emails from outside. I can set the condition "if recipient is a member of", however I can only select individual users. I do not see any groups.

Can I get some advise on how to accomplish this?

[#2]

You should see the following set of recipients:

Get-Recipient -Filter 'RecipientTypeDetails -eq ''RoomMailbox, EquipmentMailbox, LegacyMailbox, LinkedMailbox, UserMailbox, MailContact, DynamicDistributionGroup, MailForestContact, MailNonUniversalGroup, MailUniversalDistributionGroup, MailUniversalSecurityGroup, MailUser, PublicFolder, TeamMailbox, SharedMailbox, RemoteUserMailbox'''

The list does include user/contact objects, but you should also see "traditional" Groups. Scroll to the next page or use the Search button to narrow it down, if needed. Also, note that Microsoft 365 Groups/Teams will not be returned, that's expected.