Pass Data from Unity to XCode child app

I'm trying to make an included iMessage Extension app with my Unity game that changes certain values based on your progress through the Unity game. I have the two apps included in the same app group, and they work to be built together, but they don't share user default values, so I can't figure out how to read Unity's playerprefs values inside of the iMessage extension app's Swift files.

Is it possible to access the parent app's UserDefault values directly? Or is there another way to make...

Pass Data from Unity to XCode child app