This is the strengths I would be giving these building materials.
1 is the weakest and 5 is the strongest.
5 needs to be stronger than 4 so it cuts 4 away at the end of the horizontal wall.
4 needs to be stronger than 3 if you want it to cut as per your image - but if you want 3 to continue through, it needs to be stronger than 4.
2 Needs to be weaker than 3 & 4 so it does not cut through them.
1 also need so be weaker than 3 so it does not cut though and weaker than 2 if you don't want it to cut into 2.
So 1 & 5 can not be the same building material otherwise they will be too weak and 5 will not cut 4 or too strong and 1 will cut 2 and 3.
Without setting it all up for myself to test, that is what I would try.
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