Originally Posted by
DrNewGod
This was a recurring problem with YJ. As much as I loved the show, they really had to make the JL a pack of chumps from time to time to help build up the focal characters of the show. Every now and then, the writing came up with good ways to occupy the mentors (such as the Injustice Gang episode in S1), but too often, they were made to look out of touch to give The Team the spotlight (tracking down Red Tornado, for example, or not swooping in when The Team lost the Amazo components)
To the OP's question, however, there are plenty of ways to include the mentors (including Superman) that make sense, but they would all be story dependent.