I believe you are customizing your screen resolution because the Intel graphics controller supports up to
4096 x 2304, 3840x2160 @ 24Hz / 24bpp.
If your game does not allow going more than 1920x108 is because the game was developed to work at that range. This is something you need to check with your game developer, probably new patches or workarounds.
What do you mean by customizing my screen resolution? The 5900x1080 (5760x1080 without bezel correction) resolution is one of the given resolution in the resolution drop down box of the Intel HD Graphics Control Panel.
The games actually do allow resolution at that high range. I have a friend running the same game at that resolution with no problems at all, although he is using NVIDIA surround for his triple display. Why won't the game detect the resolution on my computer but it does on my friend's computer?