Hello guys! I'm in trouble... i'm a good modeler but I'm a noob in animation.

The problem is this: I'm modeling a tornado for a videogame... this:



Now, how do I make tha animation in a way that the different "belts" are rotating at different speeds and at the same time everything looping?

So basically, How can I do a looping animation inside a longer looping animation?

Thanks in advance guys!