Import to update metadata without creating new articles?

[Using OJS 3.2]
I am investigating options to streamline our workflow re: completing and updating metadata for articles that already exist in the system. We would like to avoid having to input all the metadata for each article manually.
Does the import process using the Native XML plugin always create new article records in OJS for each article whose metadata is imported? Or is it possible to use this plugin to populate & update the metadata on article records that already exist in the system?
If the Native XML plugin can indeed be used to insert data into existing records (without creating whole new articles), then how does it match records in the source XML with records in OJS to ensure that the metadata is applied to the correct article?
If the Native XML plugin always creates new OJS records on import (in which case we cannot use it for our intended purpose), is there any mechanism available to update / overwrite article metadata in bulk, using an external source (XML or otherwise)?
(I could not find answers to these questions in the Administrator’s Guide.)
Thank you for any advice!
James Rice