Cant be sure. What is the gear on your melee classes like and are you using any defensive cds? If you already have Marauder levelled you an always cross skill bloodlust.

To be honest, there really isn't many situations where you want to take on more than one enemy at a time as very few classes have decent AoE till much later in the game.

Oh also a chocobo companion with healer skills can help as well.