Quote Originally Posted by Kuwagami View Post
7 and 10 ? I might have missed that relation >_>

you forgot the whole bunch of Ivalice games, which are all interconnected.
Yeah, 10 is confirmed to be related int FFX-2. Shinra, one of the al behd, is confirmed to be the ancestor of the founders of Shin Ra corporation in FF7. They are not the same world, though, as the FFX world eventually settled other planets via space travel some point in it's distant future. Or FF7's distant past.