Is there a way to prevent the overwritting of aggregate data loaded prior to an xml file import?

I am creating a form in Adobe Livecycle ES2 where my client would like to be able to import an amount of aggregate data before a form users fills out the form. They would like to ensure that this aggregate data is not overwritten should a user import an XML file with saved answers. Is this possible?

Is there a way to export only the data capture from the end user? Is there a script that imports certain fields or protects certain data from being over written?

The end users will be using Adobe Acrobat Reader, so the functionality is most important in this product.

Thanks!