Create Exchange Online rule based on the number of recipients

[dmarquesgn]

Hi,

We're having some issues with emails sent from external domains (like gmail, hotmail, etc) being sent to hundreds of internal users.
So basically someone has an more or less old list of internal users, and sometimes sends emails to hundreds of our internal users. The annoying thing is that of course it's a different sender each new time. 

I've searched but couldn't find it. Is there any way to create a rule based on the number of internal recipients?

Except from some newsletters, it's not usual for anyone to send an email to hundred of our users. So I would like to create some rule and check if it's sending the email to more than 50 recipients, then send it for approval.

Is something like this possible?

Thanks

[#2 · Accepted solution]

No, nothing built-in that can address such scenario. And you cannot use custom transport agents in Exchange Online, so unless you are routing mail flow through some third-party service that has such functionality, not possible I'm afraid.

[#3]

Ok, thanks.
Is there any place where we suggest new features for Exchange Online?

Thanks

[#4]

Try over at the Feedback portal: https://feedbackportal.microsoft.com/feedback/forum/84b411cc-50d1-ec11-a7b5-0022481f35a4