Due to recent laws we cannot allow our employees to contact our customers through mass emails.  What is the best way to accomplish this?  
If blocking is not possible then is there a way to know when an employee sends out a mass email outside the company?

Thanks in advance.

Hi Jas,

I recommend you can consider using transport rule to block the mass mail which been sent to customers, as below:

Best regards,

Hi,

Is there any update with your issue?

Best regards,

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