USB 3.0 KVM Switch Displayport 2 Monitors 4 Computers, 4K@60Hz Dual Monitor KVM Switch with Audio Microphone Output and 3 USB 3.0 Ports, 4 Port DP Monitor Switch for 4 PCs 2 Monitors. Only when your computer supports dual display or multi display, you can use this KVM to achieve 4 PC to share 2 monitors.
eBay