I have two desktop computers in Room 1, each of which have 2 monitors connected to them (1x VGA, 1x HDMI, each). These 2 monitors are dedicated to the individual computer they are attached to, and are used "normally".
In Room 2, I have a single large monitor. I want to have the single monitor in Room 2 connected to both desktops in Room 1 in a manner that allows me to click a button, flip a switch, do a jig, whatever is necessary in order to duplicate a display onto the monitor in Room 2. Let's say the first desktop in Room 1 has monitors A and B, and the second desktop has monitors C and D. I am imagining a box "switch" of some sort that has 4 buttons, labeled A-D. When I press A, the monitor in Room 2 duplicates the display from Room 1's first desktop Monitor A. When I press the B button on the switch, the Room 2 monitor changes to duplicate B. And so on.
1) How can I accomplish this? What kind of hardware or software is necessary, and how do the monitors need to be connected and/or configured?
2) What if I also had Room 3, with the exact same setup as Room 2. Maybe I want Monitor A duplicated in Room 2, but Monitor B duplicated in Room 3. Or perhaps I want both Room 2 and Room 3 to duplicate Monitor C. How does this additional "standalone" monitor change the setup, if at all?
Thank you all for your time!