USB 3.0 box header splitter?

[Dan3345]

Ok here's a bit of a confusing one.. My motherboard has a 20 pin USB 3.0 box header, and I was wondering if anyone knows of something that I can plug into that 20 pin header to make it go from one, to two headers. Here is an example of what I am talking about. Except I need the USB 3.0 jacks to be full size 20 pin headers.

 

Is this even possible? Would doing something like this slow down the performance of the USB slots? If you are wondering why it's because, I have some USB front panel card readers I want to install, and my case has a USB 3.0 20 pin header as well. However my motherboard only has one 3.0 20 pin header. I understand I could use a pass-through but I hate doing this because I am wasting a USB 3.0 slot.. Which btw, I am frequently using for school and I really do need all the slots I can get...