How do I randomize specific tiles?

I'm bad at explaining this so I made a quick mockup picture.

Basically what I want to happen is that since I'm using the flat tiles with no decorations to build my map. I would like to create few tiles with random decorations, as you can see i quickly made with paint for the picture. And when the layout starts for every tile there is a say 1/10 chance to change into a random tile that is the same spot but has decoration on it. You know to make the game look a bit more randomized and not just a big blank box.

Is this possible to do with C2?

something like this:

on layout start if tile is "1"

change tile to: "choose (1,1,1,1,1,1,1,1,1,2)"

This should work:

+System: On start of Layout

+System: For "x" from 0 to Tilemap.Width/32

+System: For "y" from 0 to Tilemap.Height/32

+Tilemap: Tile (loopindex("x"), loopindex("y")) = 1 -> Tilemap: Set tile (loopindex("x"), loopindex("y")) to tile choose(1,1,1,1,1,1,1,1,1,2)

Edit: "32" = size of your Tile - 32x32 in this case