Curve on Curve

Hello,

I feel like this must be an easy one, but still i dont seem to find a "general" solution to my problem... Also i am pretty sure i did this already ages ago as some basic grasshopper modelling... but ... well... 

I want to cull/remove/find smaller curves that are ON another curve.

In this basic example you can see my problem, i created 3 meshes (red,not selected) and have 3 closed curves "around" them (green, selected).... The aim is to get all curves of the mesh, except those that are on the outside curves....

I am pretty sure i once had a tool for the selection of different parts of meshes, this might help in this case, but i also seek for a simple solution to pick/chose these curves/lines that are on other curves/lines...

Greetings