"boundary" curve for intersecting closed planar curves?

Dear grasshopper-community,
it seams to be a rather simple issue, but I can’t get my head around the following problem:

I have got several intersecting closed curves (black, white and cyan in the picture below). What I what to get within grasshopper is the boundary curve (yellow) around the three closed curves.
Any ideas on how to get there in grasshopper? I already tried a kangaroo wrap approach, but didn’t get very far and it seems to be a bit overpowered for that issue.

Thanks a lot for some answers!

Try this (and Sort by Length):

Try with this work with your curves, maybe you need to improve it

region.gh (14.4 KB)

wow, that really is a neat solution! Thanks for your help, I was sure there were better more appropiate ways than kangaroo2 wrap approaches!

One more approach.