How to set up multiseat on linux with one video card and hardware acceleration?

Question

linux

I read the article Multiseat on a Debian machine . But there you need two discrete graphics cards.
There is an option where one card can be integrated and the other discrete, as described here .
Found solutions for one video card:
Solution via XGL .
Solution via Xephyr .
Solution from help.ubuntu.com via Xephyr using XDMCP data transfer protocol.
But they have two drawbacks:
They are old - 2008-2012.
No hardware acceleration. As stated in this article , solutions based on Xnest, Xephyr, XGL, etc. - you can't play games like that without hardware acceleration. With hardware acceleration, it's XORG. But then you need like two video cards.
As a result, the most "fresh" solution for one video card is from 2012 using xephyr and XDMCP. Since then 6 years have passed. I'm surprised that the search does not return up-to-date options. How to set up multiseat with one video card and hardware acceleration (xorg)?
Possible solutions :
In Section "Device" of the xorg config, you need to register not only the video card, but also two active outputs of the same video card. As written in this article , this can be done by adding an additional Screen option to the Section "Device" below the BusID:

xorg.conf

Section "Device" 
        Identifier      "NVIDIA Corporation NV40 [GeForce 6800] 0" 
        Driver          "nvidia" 
        BusID           "PCI:3:0:0" 
        Option          "RenderAccel"           "true" 
        Option          "AllowGLXWithComposite" "true" 
        Screen          0
EndSection

Section "Device" 
        Identifier      "NVIDIA Corporation NV40 [GeForce 6800] 1" 
        Driver          "nvidia" 
        BusID           "PCI:3:0:0" 
        Option          "RenderAccel"           "true" 
        Option          "AllowGLXWithComposite" "true" 
        Screen          1
EndSection

Alex F found how the last way was implemented here (in 2014).
I'll post when I test it.

Answer 1

After a little correspondence with the author of the question, I found my answer here.
I give a link at his request: MultiSeat (KDE5) Kubuntu how to configure?