Referencing data

Hi, I am not sure if I call it right, but I am looking for a way on how to check/reference where the data is coming from, lets say I have two lists each containing curves that are offset by different number, lets say list 1 offset is 40 cm, list two is 20cm, now I create new line which is attached to one of curve from the two lists, how do I find out which curve from which list I am touching? I want to edit it depending if it touches first list or the letter. I am not asking for solution, just please direct me what should I be looking for, I ll search for the right tutorial afterwards. Thank you!

Your problem may have more to do with how you modeled the problem than how to solve it. Everything can be done in many ways, and not all are equally valid. You can go from A to C in one way, and get stuck there, or use another way that allows you to go from C to D. Being clearer, you should show how you have done in GH, because your description is ambiguous. (20.0 KB)