@fabulous-ferret
The way it works is there’s the game engine logic (for all maps) and there’s the map files, so yes if one map has some feature, you can make any map can have that feature, by editing the map files (mainly the xml). You’d open up the two maps in a text editor and start copying stuff over.
Anyone can do it, but I don’t know how difficult the diplomacy option is to implement or how tech-y you are