In an interview with Comic Book Resources, producer James Tucker laid out the plan as follows:

This will definitely be the first salvo in doing new movies that are in continuity with each other. Our next movie's going to be 'Son of Batman,' and that Batman will be the same Batman that you see in 'Justice League: War.' Basically, we'll have two concurrent series of Justice League movies and Batman movies, and they'll be in continuity with each other. So it's kind of world-building.