Using an Address Book custom label on a printing label
When printing labels, I find a good technique is to make a new Address Book group. Here's a technique that might work, depending on the size of the job. 

Duplicate a contact with copy/paste, and drag the copy into the label printing group. Edit the card so the name fields are blank, and set the first name to be "The Smith Family". When you're done making the label changes, select the group and bring up the printing UI, which will print the contacts in the group.

When you're done printing, delete the contacts from the label printing group, then delete the group, and your original contacts remain intact.