Outlines on shared edges objects

Hello everyone,

I currently work on a project where I want to show outlines.

-Unity version 2020.3 -Probuilder -ProGrids

Outlines material from https://www.youtube.com/watch?v=8Xq7tU5QN1Q

I have two or more different gameObjects that share edges. Unfortunately the shared edges are not outlined. Here is my issue in pictures below :

Do you know any tool that would do the job ?

I am seriously considering adding some lines with line renderer or some unnecessary 3D structures...

Thank you in advance for the time dedicated to my issue.

Have a great week end,

Francis