Here's the setup: You have a group of people who you routinely send email messages to--your bowling team, for example. The problem is that some of the team members have more than one email address and, apparently, some folks you've been sending messages to are a little upset because you've sent very casual messages to their business address. How can you avoid making this mistake again?
Launch Contacts and select Edit > Edit Distribution List. In the sheet that appears select your group and you'll see your contacts along with their email addresses to the right. Simply click on the address that you want the group email to go to. When you next send a message to the group with Apple's Mail app, the message will go where you intended.
The distribution list isn't appropriate only for email addresses. You can also choose a default phone number and street address.
And that's it. Short and sweet--a simple way to ensure that your important group messages are sent to the most appropriate address.