Getting Subdivided Boundary Curves

Hi all~ I would love to get some helps on Rhinocommon script..in c# would be great..

So I need to get subdivided boundary curves(closed) from a one bigger boundary curve. Please see the attached image.

What I have done so far to get that is like splitting a original brep by curves and getting boundaries from splitted breps. This works fine but it is slow(not super slow..but still slow) and I assume there should be a smarter way of doing this.. So if you please give me some ideas that would be awesome!

Thank you!