I asked this about a year ago. I was told it wasn’t possible through JSON yet and that you had to mess around with the mapgen code in order to get it to work. Has that changed? Just to clarify, when I say “buildings with multiple parts” I’m referring to buildings like the hospital and shopping mall. I looked through some of the files but I’m hopelessly lost. I know how to add in a single building but I have no idea how to make them spawn next to each other. Any help would be greatly appreciated.
Should be possible now.
Check out how is evac_center defined and implemented in overmap_specials.json, overmap_terrain.json and mapgen/evac_center.json