Game: Arkham City follow up?

I know this isn't film news, but in the proposed follow up to last years Action/Adventure video game "Arkham City" will include The Justice League in some capacity. That is the part that got me excited, there has been rumours for a couple of years now that The Justice League will be getting their own film. Could this be some sort of tie in to the film? Or, could it just be DC's way of bring The Justice League back to the main stream to build hype around a possible film? Bear in mind these are all my own speculation nothing with any truth to it.

The game is set to be a prequel to both "Arkham Asylum" and "Arkham City", and will detail Batman's first encounter with the infamous Joker. It will also be highly influenced by the "Silver Age" comic books, to the less nerdy among the readers that is roughly the 50's through the late 60's.

I will also add, if you haven't played either of the previous games go out an buy them NOW. They are two of the greatest video games of all time in my personal opinion, I can guarantee you will not be disappointed with them.