Have Jellyfin merge custom tasg from nfo file with default tags

[lev]

Jellyfin already allows reading metadata from .nfo files.
I would like to use the tags Jellyfin reads automagically from providers and just add some additional custom tags without overwriting them.
And I only want to have my custom tags saved in a file next to the movie

If I do this with an movie.nfo file it overwrites the other tags.

Code:

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<movie>
  <tag>my-extra-tag</tag>
</movie>

Is it possible to have Jellyfin merge my-extra-tag with tags it already picks up by default?