[Cloth] Cloth.vertices != Mesh.vertices. But then how to change coefficients at runtime via indices?

So as the Unity doc says:

"Note that the vertex indices may not necessarily correspond to the indices of the source mesh - especially when triangle stripping or UV seams are used in the source mesh (ie, multiple indices for the same vertex), cloth vertices will be different, as the cloth simulation only uses a single index for each vertex."

Then how can we change the cloth.coefficients at runtime through vertex indices?

Is that even possible ?

The reason I need to do this is that, I have clothes in different layers, when the higher layered cloth covered the lower, I need to set their coefficients for the vertices that overlap.

 

Think no ones gonna reply anyway. I just put the answer here.
Todo this, one has to "cook" the mesh yourself to get the same vertex indices as the cloth.vertices...
And that is not hard at all :
https://forum.unity3d.com/threads/finding-duplicate-triangles.142788/