Shape Keys on Curves - Logo Morphing - some help?

Hi there,

I would like to do some Logo morphing with shape keys on curves. This is fine so far,
but when it comes to the point where I want to make two separate shapes out of one,
it is not possible. If I open up a connection in a certain key and reconnect it, this applies for all of my shapes including the basis. I helped me with a cheap trick, where i shaped multiple objects and hid
them within the visible ones. but this is not the way to go. I really want it to look like one shape separates into two.
Also there are two many Issues and artifacts using multiple objects while rendering.
Has anybody an idea how to accomplish that? Even maybe with a different approach?

Here is a video that shows what I am trying to do:

notice the poor deformations at the end.

Thans for your help,