If you use groups in Address Book, you may have run into the same glitch that poenn did: When you address an e-mail to a group, and some group members have more than one e-mail address, your message may not get where you want it to, because Mail uses the “wrong” address—a contact's private address, for example, instead of the work one you wanted to use.
But you may not have hit on the solution that poenn did: You can choose which addresses will be used for contacts in a group by right-clicking on that group in Address Book and selecting Edit Distribution List. When you do so, you’ll see a Distribution List window where you can set a default e-mail addresses for each member of the group. Next time you address a message to that group, Mail should use the addresses you want.
You might also have the opposite problem: You're addressing an e-mail to a group and you want it to go to multiple e-mail addresses—work and home, say— for group members who have both. Many years ago, another Hints reader found a solution to that problem:
First, create two groups—
groupname home and
groupname work, for example—and add contacts to both. Next, select the first group and (as before) right-click and choose Edit Distribution List. In the Distribution List window, select Home from the Change All Labels dropdown. Now do the same for the
groupname work group, but this time select Work from the dropdown. Now create a third group—
groupname—and drag the two other groups into it.
Now in Mail, when you type
groupname into an address field, both work and home e-mail addresses will appear for every user who has both. If you have users with more than two addresses, you can repeat the process accordingly. Also, if you only occasionally need to send to more than one address for a single recipient, you can always enter the name more than once in a Mail address field and then select his or her various addresses from the dropdown.