I have around 20 computers in my lab. We have a router and a 24 ports switch. We connected all the computers to the switch and switch is connected to the router. We could able to access internet in all the compters.
However, when we tried to access one computer from another, we could not browse them. Some of the computers are not even shouwing in the network.
When I see, some of the are connected as "Network1", some of them are connected as "Network" and some of them are as "Network2" and Some of them "Network3".
It sounds like you have different network IP address configurations from device to device, and it's very likely that this is caused by having VLANs configured on your router/switch which will separate the networks and often block access from different groups of computers.