You need multiple HDMI switches, one for each monitor that may need input from more than one computer. So for your example, two of the monitors will need to get their output from corresponding HDMI switches, and those HDMI switches will need both "development" and "A" as their inputs. This will allow you to switch "A" from having one monitor to three monitors, stealing monitors from "development".
Using VNC or X11 forwarding is likely to be a more convenient and cheaper solution. Or virtualization, if the only reason you have multiple machines is to run multiple OSes.