Struggling with layering in Phaser

[J4G]

I'm creating a game with many types of tiles. Each tile type has different properties that I'm customizing: it's texture, layering, and collision. These are all determined separately. In the interest of making my P2 life easy, I have two tile groups, collision and no-collision. The tiles that collide with the player are placed in one and the others go into the other.

 

The problem is, as I mentioned before, my game is pretty layering-intensive. As of right now I haven't found a way to have individuals tiles within a group have an index independent of their parent group's. This makes sense of course, especially when you're familiar with the Pixi renderer. That doesn't really solve my problem however. Does anyone know of a way in which I can keep my collision groups separate from my layering? I would love, love, love if Phaser 3 had some sort of Z-index setter as well- manipulating everything through bringToTop() is pretty difficult.