You have a device labeled "network switch" but you show it as a physical switch. Do Simulator 1.x and Real Instrument 1.x have the same IP address and you are physically switching the connection, or do they have different IP addresses?
Regardless of whether you are using a simulated instrument or a real one, if your instruments are all assigned on the same subnet but they are not physically connected to the same subnet this won't work. If the real instruments are physically connected on the same subnet, such that any of the PXI ports can talk to any of the real instruments, then you should connect the simulated instruments the same way. If each PXI port should talk only to a single instrument, then that pair should be on a unique subnet. You may be able to do this without changing the IP addresses too much - you can keep them in the same 192.168.0.x space and use the netmask so that you only need to change the last octet.
