Typical buffs as I have suggested on all of the other help threads you have created. That is Haste, Protect, Shell, Bubble, Bravery, Faith, etc. Decoy on your tank (main fighter).

Have your main fighter with a gambit that forces him/her to attack the monster with the highest HP. I forget the exact name of it. "Foe: Highest HP" or something like that. :P

One person designate with the gambit "Ally: Heal >50%" or whatever the appropriate name is.

One person should constantly spam the undead mobs with your highest cure all spell. Cura or Curaja. One of the two, I think. You can also use Holy if you have it, but that only attacks one at a time. Make sure the person doing this is spending the least amount of MP possible (use the licenses for this). And have them use Ethers on themselves if their MP gets below 20-30%.

The healer should keep the buffs up on your main character. And remember that Roblon is effected by Slow, Blind, and Sap, but not any other status effect.