There actually was at one time an animated film planned for the series to bridge the gap between it and the successor series Justice League Unlimited, but the project was scrapped.
Years later, the plot for the film was used for Justice League: Crisis On Two Earths and featured no connection to the animated show.
For that reason, Kevin Conroy stated that he always preferred stories that focused on Bruce’s outsider status.
If a Justice League reunion film did happen, there’s a chance both Conroy and Susan Eisenberg could get their wish, as the original project managed to tell some pretty interesting tales throughout its run.