It seems what you would need is a spreadsheet with the first line having the categories and then each row containing a person's information. If done right you can import any number of addresses. Example would be:
The USPS program's address book format for CSV is like this:
Full Name,Company,Address 1,Address 2,Address 3,City,State,Zip Code,Province,Country,Urbanization,Phone,Fax,E Mail,Customer Ref #,Short Name
Joe Customer,ABC Co.,480 L'Enfant Pl. SW,,,Washington,DC,20024,,United States,,2022222222,,icustomercare@usps.com,,ABCCO
Code:
Name Address City State Zip
Abra 123 Cad Abra AL 12345
etc 234 etc etc TX 23456
Full Name,Company,Address 1,Address 2,Address 3,City,State,Zip Code,Province,Country,Urbanization,Phone,Fax,E Mail,Customer Ref #,Short Name
Joe Customer,ABC Co.,480 L'Enfant Pl. SW,,,Washington,DC,20024,,United States,,2022222222,,icustomercare@usps.com,,ABCCO