Shape Keys on Curves - Logo Morphing - some help?

Hi there,

I am trying to to a logo morph with shape keys on curves.
It works fine but I am missing the possibility to get from one curve to
two curves from one key to another. If you open up a loop and connect them
differently to get two loops, this happens to all your keys and destroys all the other keyshapes
and basis. I want to morrph one form to two forms, but this is only possible with a cheap trick,
hiding the other curve within. To show you what I mean exactly, I made a video:

Is there anybody who could tell me a different approach or is there a button which makes it posible, i just didn´t see?
Thanks for your help!!