One aspect upfront, “astro_sun_local_position_elevation” is not a thing, it’s an item in your system automatically linked when you imported the astro thing through PaperUI.
Answering your actual question: Only items and/or groups mentioned in your persist file will get persisted. Thereby, looking at your file above, the groups Ned will not be persisted to begin with.
However maybe I understood you or your setup wrong. This might be helpful: Default Persistence Service