I am sorry you are having problems but let me help you.
I am having problems to understand the term bifurcation in a single Pci-Ex slot or understanding your query but I recommend you checking the Intel® 7 Series Chipset Family PCH: Datasheet. In the case that you do not find the information you are looking, please elaborate more your question or explain more about your query.
Thanks for waiting.
I found answers to my questions.
This issue is no longer relevant.
I ask you to delete this topic.
Thank you for your attention.