The studio is already working on two standalone movies involving Justice League members The Flash being written by Marc Guggenheim and Michael Green who also worked on the Green Lantern and Wonder Woman, Michael Goldenberg scripting here.
It's not the first time WB have tried to get Justice League of America off the ground in 2008 plans were shelved that would have seen Armie Hammer playing the part of Batman, Adam Brody as the Flash, and Megan Gale playing Wonder Woman with George Miller directing.