Hmm, I guess there is a hack to solve any problem, but adding layers to make a connection that is later to be done by a physical wire or connector is just not the ‘royal way’. An other problem with this approach is that my PCB manufacturer accepts native KiCad files as production input. The last thing I want is confusion about the number of copper layers that must actually be produced.
True, and thanks for the tip. 
Separation is not a problem for me. The PCB i showed was just quickly made to show an example. My actual use case is much more complex, and has all the cuts and mouse bites required.