Nope, each device has its own set of information and will not become automatically linked to another device, even if they are the same model or are in the same network. If, however, when you finished the registration process with your device and found different users there, that means those other users registered using the same device (as in, physically, the same tablet).
However, there is Samsung's Link, which forms a "Samsung" Network if your devices are connected in the same WiFi. But even so, you still have to grant access to the other devices so they can 'see' your stuff, and this is usually just to share pictures, music, and some files.