Group PolyCurve if is inside another

Revit
1

So I have a bunch of polycurves, how do I group this curve if one is inside another?
These curves represents the perimeter of floors, and I have a feel of opening in those floors.

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Like this one in the image, I have a big curve with a small curve inside, I’d like to put it into lists, if one curve is alone the list will have only one item.

Thanks!

2

Have you tried group curves from archilab, could probably help