There are all sorts of ways. If you already sorted the white lines based using the Sort Points component, you can get the top points of the red lines, sort points again, and then use List Item on the curves with the indices output from the sort points component.
Another way would be to get the bottom points of the white lines and use the Closest Point component to the top point of the red lines. This will give the index of the closest point which you can then use this with List Item, as above.
Its best if you could upload your gh definition, internalising any geometry referenced from Rhino.