Separating Bible translations from Stories and Songs in Book Collestions

I’m trying to add songs and articles to an app that already has 4 languages. It adds them as book collections that appear with the the Bible translations.
Screenshot 2021-09-20 at 10.29.01
This is what one would expect, but in the app when you use the Bible in diglot mode the articles and the songs appear as an option along with the other Bible translations.

If you choose one of them they appear blank because the panes are linked and only the main language is allowed in the top pane.

It would be better if these did not appear as Bibles, is there a way I can do that? Is there a way in Book Collections for me to separate them?
I have already changed their Book Type to Story Book and Song Book respectively.
If this is not currently an option, can I suggest it goes here as a third option so a Book Collection can only be accessible from the Contents Menu?