relativ distance problem

Hello,
in my gh definition I need to adjust the distance between two points by two options: in relation to each other (hierachically) and in relation to a startpoint 0/0/0 (equal)

1. option: the first point depends to 0/0/0, and the second point depends to the first point.

2. option: the first point and the second point depends to 0/0/0

My problem: when i switch between the two options the second point jumps from one value to the other because of the two sliders, but i would like to have the point in both options on the stays at the same place.

Does anyone know how to make it, ideally with only one slider for both options?