I am pretty new at Gimp, so not sure if this is possible at all.
Let's say I have two lines like this, and I give the impression one line is on top of the other by clipping at the intersection, like this:

Now let's say those two lines are in different layers and I want this "clipping" to basically be transparent (not just white), is it possible to do something in the layer of the line on top to force transparency in the layer below?
I tried to play with layer masks, but did not have any luck...