Outlook - Confirmation popup if sending to different domains?

[bushmills]

Hi
I just wondering if it is feasible for a code to read the email receiptents and automatically popup for confirmation if the list of people are from different domains.

ie
To: John@ABC.com, Steve@abc.com, Bob@ZYU.com
Because Bob is from ZYU then the code will catch that and popup a message for user to confirm if this is ok.

Nothing happens if the domains are all the same or the 'different' domain matches the Senders own domain.
ie.
To: John@ABC.com, Steve@abc.com, Bob@BCD.com
sender: Joe@BCD.com

might be easy for some experts out there

thanks!