https://www.amazon.com/PCI-Express-Video-Y-Splitter-Adapter-Supply/dp/B00A3OVG4W/ref=cm_cr_arp_d_product_top?ie=UTF8

Would this work for a GPU/PCIe riser?

Also, would it matter having those two ground cables on the 8 pin connector? I know you can get the cheaper 6 pin splitters for around ~$4.