I am trying to add hill and edge biomes to my custom biomes. For example, plains have forest biomes as a hill biome and extreme hills have extreme hill edges. Before, I just modified GenLayerHills and GenLayerShores but this makes it incompatible with other mods that do the same thing. Is there a way to add hill and edge biomes to my custom biomes without modifying base classes? If so, how would I go about doing it?

Bump, I also need this knowledge

I had to redo the GenLayer for my mod .

So ultimately, base file editing was necessary?