In vanilla, a farm can be built on any terrain, as long as it has access to freshwater, due to it having FreshWaterMakesValid to true. What I want to do is to selectively enable and disable freshwater farms. For example, I want the farm to still be buildable on tundra tiles next to freshwater, but no longer buildable on Snow tiles next to freshwater. How would I do this? Is there a way I can mod it through the xml? Also with HillsMakesValid, is there a way to selectively disable building mines on top of hills of different terrain? ie. desert hills can no longer have mines on it, but other hills still can?