Select objects outside a curve? Rhino 5

Hi everyone, I’m working on a model and I need to select all objects that are outside a specific curve and then delete them. Or if I wanted, inside a curve. I have a very large model so I need to streamline the process. In the screen shot below, I need to delete the white curves outside the black outer line and the white curve inside the offset curve, and keep the white curve in the middle. Any ideas? Thanks

If you are willing to use a bit of Grasshoppering you can solve this fairly simple. See the attached files for a basic case:

GetFragmentsBetweenCurves.3dm(45.5 KB) KB)

And here are a couple of scripts to do the same…