Is it possible to prevent external emails being delivered to a group's guests?

Question

We have a 'sales' group that is primarily used for document storage and incoming emails from marketing campaigns and the like. We have guests on the group that are third party consultants and not on our domain.

We had to make some exchange rules, that work ok for now, to prevent the sales incoming email from being distributed to the guests.

But we consider this a potential data privacy concern if incoming emails are, by default, automatically sent to all group members, especially guests.

Perhaps this should be a setting somewhere?

Answer 1

You can remove them from the "subscribers" list:

Remove-UnifiedGroupLinks groupname -LinkType sub -Links "guest_domain.com#EXT#"

Answer 2

Hi,
You can prevent external emails sent to a group:

Set-UnifiedGroup -Identity "Internal senders only" -RequireSenderAuthenticationEnabled $true  

But if you want external messages being delivered to the group but not delivered to your guests, I'm afraid the best method is using transport rule (you may not want removing the guests from the group because all messages won't deliver to them after that)

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