How to get the section index of a procedural mesh

I’ve setup a procedural mesh component and I’m adding geometry at different sections.
I’d like to retrieve the section index when performing a line trace, but I see that there’s no such output in the break hit result, I expected the Hit Item to work but it always reports -1.
I’d like to be able to draw polygons at runtime and then to pick them or delete if needed, any suggestion?

iterate all sections in the hit component,find the triangle containing the hit point,see: