I need a dropdown to insert a tag into CKEditor

Hi All

I've searched here and can't find what I need, hence this post.

I'm using CKEditor in a mass mailing contact manager and would like to give the user the choice of selecting from the CKEditor menu a dropdown with things like  "first name" or #firstname#.

Have you ever used the program SendBlaster which uses the same system?  When you send the email the contact manager looks up each recipient's first name and replaces #first name# in the text, so you get an individual email.

And pointers please?

Thanks

Nick