exporting a field from dev to production
At Drush Commands something similar is mentioned in the comment of Sebastian Contreras:


  --partial and --source "custom directory" are not working at all after upgrading Drupal 8.3 to Drupal 8.4 and Drush8 to Drush9.
  It does not detect the source with --source and it does not detect the --partial causing lots of removals where they should not happen.


However, did you already try the Configuration Split module? This module allows you to create different sets of configuration stored in multiple directories, and merge them back together when needed/indicated.

I'm using the Configuration Split module mostly to exclude configuration that is only needed in my development environment and not in production (modules such as Devel and Stage File Proxy). If I understand your use case correctly, this module should be able to perform the thing you want.