CiviCRM's database already contains a Custom Greeting field which is ideal for non-profits that want to use this data for mail merges (or perhaps later on for mail merges). Since the field isn't exposed in the edit screens right now, you cannot manipulate the data once you import it. You can simply export it. The Custom Greetings input field should be added to the basic contact data fields in each type of contact's editing screen so the data can be changed, logged, and updated.
Add the Custom Greetings field to these edit screens and hook it to the existing Custom Greeting field. Thanks.