Help with OS X's Mail App →[More:]Any way in OS X's Mail to force it to mail from certain accounts depending on who you're mailing?

So, if I enter an email address (from my address book) to write to a MeFite, for instance, I want it to automatically switch to my mefi@... account. If I'm writing to someone personal I want it to come from dobbs@... and work clients from another address, etc.

Sometimes I forget to switch the account drop box which results in a bit of a mess depending on who I'm writing. (Work clients, for instance, wonder what the fuck victoryshag.com is and I don't want to explain it to them.)

Entourage will do this, if I remember correctly. What about Mail? A hack? A plugin? Something I'm missing in the prefs?

Danke.