Hi Taylor
You cannot simply copy the customer master file from one company to another - you have to export/import it.
As for the ship-to addresses, until OE 9.0A is released, you can copy the files OESHTO*.xxx and OESHTE*.xxx (where xxx is the extension). Just make sure that the two companies have identical tax groups and price lists.
As a precaution, make a backup of your target company's data before attempting this.
Steve