When I am sending a letter, often times my letters are requested to pull first name and spouse or additional salutations. ie addressing our Hispanic or Asian groups. We have multiple salutations for these groups. Please consider this a priority for update within Mail function
You have option in mail to pull from any of the addressees/salutations have formatted. You can chose to use one with nickname. You have option of two. I would not want to see more than one actually pulled into a letter.