How to Disable or Hide Comments on a News Post

@nickh To the best of my knowledge, here goes answers to your questions:

Is there a way to disable the "Comments" on a news item? - I don't think there's one such.

If not, is there a way to hide the comments written by other users? - I don't think there's one such.

The users that can see this news item are in a group. Is there a way to set up the group so they can't see each other's comments on a news item? - I don't think this is doable, because the security is always associated with the feed entry but not with the comments associated with the feed entry.

And an indirect solution to your questions could be is, making a different feed entry for different group of users. Simply speaking, hiding the ability to comment or hiding comments on a post can be done only by making the feed entry invisible by applying the security constraints. Let's see if any other practitioners could come up with a possibility of doing the above.