Maybe you could set it to 3 player, and have the third player's part of the screen off the real-life screen. It may mess up scoring and stuff, but as long as it's only one player getting a DNF, the game should be able to end each race properly.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT