Thank you Jerry
Hello torreydale,
yes I have KVM switch box, between nearest computer to the desk, and the external hdd.
The KVM I have can only do 2 computers. I have another KVM for the other 2 for desk#2.
Update -
I have a KVM that does all 4 computers now on desk #1, and also I have x2 of 4 switches for USB, one switches the usb mouse, the other switches the printer.

Hello torreydale,
yes I have KVM switch box, between nearest computer to the desk, and the external hdd.
The KVM I have can only do 2 computers. I have another KVM for the other 2 for desk#2.
Update -
I have a KVM that does all 4 computers now on desk #1, and also I have x2 of 4 switches for USB, one switches the usb mouse, the other switches the printer.