How can I create individual migration groups - one for each XLM file, without having to write a new migration class for each file?

I have dozens of XML files waiting to be imported into Drupal using the Migrate module and API.

Currently, all my migrations are registered under a single group called Questions as shown below: That single group of 222 imports represents 5/6 of my XML files. If I import the pending dozens of XML files, I will have upwards of 10,000 imports.

What I would rather have is each XML file having it's own individual group. That way I can revert a single XML file where necessary instead of all them.

Can anyone help me with this scenario?