Choose correct account when emailing certain people?

Hi, I did my search, but no luck. I have 2 email accounts. When I compose an email to one of my contactsm is it possible for a program to automatically switch accounts (from fields)?
Theres no option in contacs or rules or categories.

When composing, you have a drop down menu on the toolbar (next to the encryption button, look like a lock) to select the account that you want to send from.