I have a simple solution, if anyone has a different one, please post! I have the main tilemap, non-solid, the solid one and a "solids" variable that looks like this: "0,1,2,5,6,128,234,456" and contains the ids of solid tiles. At start, it loops through all tiles on the non-solid tilemap and compares them to the variable. If a tile matches, it is set in the same position on the solid tilemap and removed from the old one.