"Match entries" on fields other than ID

I understand how to export to a csv file, update the file, and then re-import using the "match entries" options. However, there are many times when the data I want to update is already in an Excel file. It would be extremely useful to be able to specify which attribute (Name, Contents, etc.) should be used to determine if the new entries "match" the existing entries. That way I could simply import my new file, rather than having to manually update an exported file.

Would it be possible to add this capability?