Group curves by region/surface

Thanks @Rajeev2

Do you think there is a way to group curves that are between two quadrants, depending on the amount of space they occupy in one or the other quadrant?

If you look at the border of the quadrants there are curves that are in the first quadrant but their area occupies much more space in the other quadrant. I would like to be able to make the curves stay in one quadrant by filtering this.