Way to check for duplicate emails addresses in a message?

[R. Scott Ohlgren]

Title: Way to check for duplicate emails addresses in a message?

When ever I send a message to a large group of my Address Book, I find that the easiest way to do that is via the Custom View. I’ll highlight all names in one particular sub set, and drag them into my message. If I have multiple sub sets I’m dragging in, a problem arises when I have some people associated to multiple sub sets. They end up getting the message 2 or 3 times.

Has anyone written a script that checks the emails of a message for duplicates, before one sends the email?