Automapping empty output

Is there a way to make the output layer in rules empty? This is mainly to prevent the player from putting tiles on the wrong layers. I tried setting the output empty and nothing happens.

Not entirely sure how to use : “DeleteTiles” option if this is the way to check if a tile should* be on a layer . Where do I specify which tiles to delete and which to keep ? I don’t understand the behavior of “DeleteTiles” , on how to make it keep certain tiles on a certain layer

Also how does automapping fit into groups? How would you select a tile layer inside a group?

For now I guess I’ll make the output a transparent tile and zero it out when parsing.