User Profile

I am making an iOS app using CloudKit where a user can make a post with some content (title, images, body, etc.) and I want them to be able to share that content using a CKShare for viewing only and have the participants post comments without the ability to modify the original post or delete it. Not to unlike Instagram, etc. Is this possible? What would the data model look like?Using the Photos app and its shared albums as a reference, participants can post comments, like posts, etc. but they can also delete images which I'm trying to avoid. I'm looking for a better security model than "just don't put a delete button in the UI".Ive done this easily with Firebase and their granular ACL controls but don't understand how to do this with CloudKit.