This setup works on most HNMs in the game and relies heavily on two factors:
The "Tank Party" usually looks something like this:
The other two parties in the alliance are usually for DDs, including a black mage party of blm, blm, blm, blm, blm, refresher. A thief party is sometimes subbed into the alliance to make the final blow.
Using this strategy, the summoners take turns using Aerial Armor to give the paladins shadows. Then, the paladins bounce hate off of each other as their shadows go down. With the bard and red mage providing refresh and ballad, the paladins can often heal themselves, and the summoners won't run out of mp. The key is to make sure the paladins are fairly equal in their +enmity stats.
In place of using summoners, using two mages subbing summoner will also work. The most common alternative is rdm/smn.
A bard can be sacrificed from the lineup in exchange for a third summoner. This also allows the summoner to add offensive blood pacts into the overall damage.
By essentially building an alliance around paladin tanks with shadows, this setup is without a doubt one of the most effective in the entire game.