As far as i know it's really not possible..
Imagine a map that you want to play with a pal.
Who gets that depot that is already placed on the map?
Sorry, that assumption is not valid. Running a company based on economic scale is too easy in this level of simulation.
I and my friends play CIM2 as Simcity 4 (curve road enhanced editon). We just build cities like we did in Cities XL 2012.
If anyone can help me find that thread, that would be great.
Obviously if it could place depot in map editor, that surely wont be a in game modification.