3 monitors + 3 system units = 2 modes?

Question

Iron

Comrades, please help solve the problem.
Imagine that there are:
3 monitors
3 system units
1 keyboard
1 mouse
You need to connect them according to this scheme:

And ensure operation in two modes:
1. Keyboard / mouse common to all computers. You need to be able to switch them between computers. Each computer broadcasts video to its monitor via DVI wires.
2. All three monitors are combined into one, a la SLS (Single Large Surface). A video card that allows you to do this is installed in the second (fancy) computer. A keyboard/mouse is also connected to it. Windows 8.
The first and third computers are budget, presumably on Debian.

Answer 1

I think so, a mouse and keyboard are connected to PC-2, Synergy is installed on all computers , monitors have at least two inputs, VGA and for example DVI, respectively PC-1 and PC-3 are connected to monitors via VGA, PC-2 is connected to the monitor M-2 over VGA, and to M-1 and M-3 over DVI.
When the first mode, monitors M-1, M-3 enabled VGA input, when the second mode, then DVI.
This is, of course, if there is a network connection between computers and Synergy supports installation on the OS of these computers, if not, then KVM is iron instead of Synergy.

Answer 2

KVM switch as an option, such in server rooms are usually installed so as not to switch the keyboard mouse and monitors,