In the current (0.8.7) version of the game, in the production of the new film you will see option “sequel”However, it does not have any significantly on the fate of such production. When I started to wonder how it would look in the final form of an implementation of this functionality I've come to the conclusion that it should behave quite differently than it used to be I thought.
So here is how to look the sequels made from version 0.9.0 Movie Business 2.