Outlook Express 6 mail question

I have searched and am unable to locate an answer for my question so thought I would give MG a try.

I have 3 email addresses I use in Outlook Express6 and one of those 3 is the one I use to send emails to my child's teachers. What I would like to do is set it so that anytime I email any of the teachers that it would automatically send that email from my specified email address even though it isn't my default email. As sometimes I forget to toggle between the 3 email addresses and end up sending it from a different email address than what I have given them on all the papers. So is it possible to be able to more or less assign to certain contacts a specific email that I wish to send them an email from without having to toggle between my multiple email addresses before sending?

I hope I have explained clearly what I am looking to be able to do if not let me know and I can rephrase it.

Thanks,
SW