Import Duplicate Detection with Related Fields

I had a non-db field added to the duplicate check screen on the import process, but that field no longer displays.  It was made up of the first_name,last_name, and account_name fields.  This no longer appears on the duplicate check dialog.

I then created a non-db index for checking duplicates.

https://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_12.0/Data_Framework/Vardefs/Specifying_Custom_Indexes_for_Import_Duplicate_Checking/

But in the SugarBean class (data/SugarBean.php), when fetching indices, it excludes any index that has contains a non-db field (line#1101-ish). I need to check the combination of last_name + first_name + account_name.  Account name is a non-db field, so this method doesn't work.

Do I need to extend the ImportDuplicateCheck (modules/Import/ImportDuplicateCheck.php) class to build this in for contacts, or is there a better way to do this?

Thanks!