Is "see through" outline possible without rendler layers?

[thmxv]

I am using this plugin to outline the selection in an editor like application. However when selecting multiple objects one outline gets invisible in some parts (sometimes not visible at all) when one outlined object is on top of the other:

I think this is avoidable using render layers, but this would requires using as many cameras and render layers as there is selected objects. Is there another way to avoid this behavior? I tried pretty much anything and read the code and examples but could not figure out if it is possible as is or with changes to the code. If this would require changes to the code, can you point me in the direction of what and where those changes would be. Also, would you accept those modifications in this plugin?