How to reorder single tile groups within a tile set of SpriteKit?

Question

In Xcode's SpriteKit, a "Tile Set" is a collection of "Tile Groups".

In the editor, these Tile Groups appear in a certain order (top to bottom) based on the order in which you created them.

Two questions:

1. Is there a way to RE-ORDER the Tile Groups within a Tile Set? I've tried dragging them within the Set, but that doesn't work.

2. When I DELETE one of the Tile Groups, it causes a problem in all scenes using that Tile Set. Specifically, it appears that any Tile Groups that are later (lower) in the list than the one I delete shift in the scenes to be ONE GREATER than their previous position. E.g., what used to appear as Tile Group #12 will now appear as Tile Group #13, and so on.

I've search here in SO and via Google but have not seen anyone describe this.

Thanks.