There is no method to import the data into the field.
We do have a "Feature Request" form where you can vote on popular existing ideas or add a new one of your own:
As to building a relationship, it depends on what you need to do. FormsCentral has "Show/Hide" logic where you can show or hide items based on the selection/s of other field/s. There are both "Page Skip logic" and "Show/Hide" logic, this tutorial shows how to use the Skip logic and doesn't really cover show/hide logic but you should get the idea: https://www.acrobat.com/formscentral/en/library/skip.html