Testing two lists of numbers for similarity

Hello everyone.

I'm trying to weed out the naked vertices of a mesh from a sublist of vertices that I have taken from that mesh that contains both clothed and naked vertices.

To do this, I'm trying to compare whether the index of the vertex in my sublist can also be found in a list of all of the naked vertices of the mesh (thanks to the Kangaroo component). And then use the list of booleans to dispatch my sublist into an even smaller list.

How can I do this?

Right now, I'm testing whether any of the indexes in sublist A, with 52 indexes, are equal to any of the indexes in list B, with 240 indexes. I'm grafting list B so that it compares each number in list B with all numbers in sublist A. So now I'm getting a tree of data broken into 240 branches containing 52 points of information... and if the index in sublist A matches an index in list B, one of those 52 points of information related to that index's branch will return "true" but the rest return "false". It seems way too complicated for what I need to do. 

Pic attached.

Thank you for any help you can give.

Best,
Eike