Import Multiple Authors via RSS/XML

We have are running WP Single User with multiple Authors. We have a large number of Authors (400+) with an XML file for each one we would like to import. By default, the RSS Import feature imports a post under the Admin user. We figured out how to manually modify the code of the importer to specify which $post_author to set which Author to import for (See previous post) but I was wondering if anyone had a solution to update this import script to automatically detect the author by using the RSS <author> tag in the same way that FeedWordPress does when it runs. This way we wouldn’t have to update the script each time we needed to do an import (which means only one person can be doing an import at a time for a specific author).