3
No, just having different SSIDs as per your diagram would put Computer B
on the same network as your other machines. It would be able to communicate with everything else on your network.
The SSID is just used as an identifier for the wireless connection your adapter will connect to. Beyond this, it will communicate with the same network.
In order to solve your problem, you could look into setting up VLANs, which would allow you to segregate traffic from different parts of the network. You may need different (more advanced) hardware to configure this.
If the VLAN feature exists on the AP but not the router with AP function, can I get this done or I will have to purchase another router with VLAN feature? – bobo – 2016-01-25T13:21:45.850
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VLANs are usually defined at a switch level, so it would be possible if your AP point can do that. Further reading here, it's quite a complex subject.
– Jonno – 2016-01-25T13:51:09.8231
Both computers join different SSIDs, but their network is the same (192.168.0.0 nm 255.255.255.0), so based on this picture they will see eachother.
1There are devices on which you can simply isolate the computer (isolate LAN). This would normally be found on the configuration tab Wireless config or security. – Terry – 2016-01-25T13:34:01.003