Different email address by group

Fortunately Address Book lets you set a default email address to use for each contact in the group. What’s more, this is on a per-group basis, so you can use a contact’s work email for one group and their home email for another group, for example.To do all this, choose Edit > Edit Distribution List. Click a group in the left column, then go through each email address, clicking the address you want to use for each contact the selected address is in bold:

via Mac Address Book tips: 5 more handy hints — Reality Distortion: Macs, Mac OS X, and Apple stuff.