Split a set of Curves with another set of Curves

Hello all,

It may sound a straight forward question but whatsoever that reason is i cannot find what is the correct way to split 2 sets of curves
In the attached file i have a set of horizontal curves and another set with transverse curves

While with the following definition i (somehow) managed to split almost every curve i dont know how i can group them back as per input set.

Any advise would be really helpful.
split_curves.gh (40.6 KB)

One possible option:

split_curvesOption1.gh (41.6 KB)