This mod creates teams and also modifies the map to have separated secure starting spawn areas.
It's still work-in-progress, but you are now able to create forces, join them and set the diplomancy of those forces.
You are also able to clone the spawn starting area, but it's ugly atm.
So feel free to update the mod inside of factorio and let me know if there any issues.
Version 0.1.0 tested on Factorio 1.1.3 on 03.12.2020