Constraints. How to control which curve is master and which’s is following

Hey there.
How do I control which line is the master line so that the other one is going to change accordingly? In fusion the order of selection decides that. In the given example I want the longer line to be equal to the shorter one, but its always the other way around.
I ve been facing the same problem with all the other constraint when using it on two unlocked curves. Sometimes a huge geometry, consisting of a trillion pieces moves to one tiny line.
Thanks

no ideas??

You can lock points on the line?

Yes. I know =) I was wondering about the hierarchy of clicking. If there is any system behind it like in fusion360.

You can also use the mirror tool. Delete the line and mirror the longer line to the other side.

Yes, thanks for your help =) But it´s not about drawing the two identical lines. It´s a general question regarding the system of constraints.

Danke Pascal!! Cheers from Berlin