unnecessary section curves , how to get rid of them?

hi all, first post here:)

I'm developing a not-orthogonal waffle system, using the normals of the surfaces to build the section planes.

Now, my problem is that on certain surfaces the normal plane can generate 2 or more distinct section curves, some of wich are not "valid" (usually only the last curve in the tree branch is valid).

That curve(s) occurs because the plane interact with another part of the curved surface where it's not supposed to.

in the next image the section planes have been highlighted with numbers from 0 to 6. you can see that i have 2 invalid section curves between planes 3 and 4.those are the byproduct of the section planes marked as 0 and 1.

I tried with vb net but i'm not good with vb.

i tried with the equal operator but unless i use cross reference i cannot find the matches.at that point i cannot find a way to know wich points were found to be equal (AKA i dunno the correct item index).

This has to be very simple because i couldnt find anything anywhere,perhaps i'm just a couple of clicks away from the solution.

my inputs:

imagine i need 3 sections:

a curve list tree with 4 curves ,one of wich is wrong

the curve endpoints from the above curves

the 3 section planes center points

I attached the definition and the model if that can help to sort it out.

hope you can help, i'm pretty stuck on this!