Trimming colliding curves

Hi,

I am trying to make a bed for the water pipes (30cm offset & -15cm down) but I have issues after offset curves to trim the more upper ones away.

I tried exploring loft > brep options and curve l curve, but nothing seems to be working.
Any tips?

Putkikaivanto.3dm (113.3 KB) Putkikaivanto.gh (16.1 KB)