I checked your capx but it doesn't solve the problem. Forget my project it just makes it more complicated.
And just look at the picture Ashley sent.
It is the painter's problem. Because of the Painter's algorith Construct 3 uses it's impossible to make Green over Blue and at the same time under Red.
The best solution is exactly what Ashley said: cut the geen in half. And layer one part over Blue and the other one under Red.
But I actually solved it on my own^^; because in my case Green is pinned to Blue. I can have Green at the highest layer and erase the overlapping part between Green and Blue.
(So it looks as in the Painter's problem photo but the only difference is that the overlapping part between Green and Blue is erased)
If that makes sense.