Hello! I have polygon layer whose outlines I need displayed in a specific way.

I want different colors for the outlines, because I have polygon layers below it that are also colored.
But as the layer draws, certain polygons appear over others. In the image above, the yellow polygon border appears on top of the cyan one.
What I want to do is have BOTH polygon outines displayed at the same time. For example, where the cyan polygon borders the blue one, I want a 6 pt ouline that is 3 pt yellow and 3 pt cyan, on their respective side.
I have tried using different settings in the symbol layer drawing options, but it won't let me place all polygons in the same level.