Just tried Call of the titans spell....no luck. It manages to move some units to a tile I choose but not the group stuck behind the gate with my main character. Have a feeling it is a bug. Any other possibilities before I restart lol!
Is one of your champions still outside? If yes, then you could go the Master Quest-route just far enough to free them (move the champion to the first gate). However, if the game considers the Master Quest as already too far advanced (i.e., kill Waerloga) then this might not work. It is worth a try though.
In any case, you have my sympathies. I had a similar problem (stuck between the two gates) happen to me a few times before. In each case due to being kicked out of enemy territory.