These devices (how funny is that, both same ISLAND!) CANNOT be linked together, but are linked together by an account, not by devices!
In order to gain access to the device, you have to be logged into an account, typically a MAC, or PC!
Now, it is possible to have a stand alone IPAD if you paid for the CELL card for the pad (NICE!), and a fat DATA plan (NICE!). It still doesn't mean you could tether the two devices together!
You NEED a middle man (PC or MAC) to get those types of NICE features to work!