I just call it the 3T group for short. Here's the template.
DPS Healer or another DPS
I once ran this group for 8 hours straight in scenarios and never lost once. (The reason we were running the scenarios was to get a Royal Crest for someone in the group. It never dropped.) The version was with the 2 DPS and Healer rather than DPS/DPS Healer/Healer. So obviously, our healer was often jumped on quickly by the enemy and we had to keep him up at all costs.
When you are using the DPS Healer, he is responsible for rezs so the main healer can continue healing the group. If the either healer drops, the other healer will have to get him back up quickly, so one tank uses morale to cover the group until the healer is back up.
The reason I prefer the DPS Healer to the second DPS in this group is the extra rez and the element of confusion this presents to the enemy. With only one healer, it's easy to pick out the key to the group. With two, it takes longer for the enemy to figure it out.
The basic idea of the group to use tanks to make one healer do the job of three. With three guards and challenges, there's no reason the DPS and healers should get hit for full damage ever. The tanks will rotate and call challenges to prevent overlap. I like to have 2 tanks go full out DPS including Focused Offense, the 2 suicide tanks, and have the last in a regular DPS kit without FO, the DPS tank. Ideally, you'll use one of each tank. A challenged target hitting someone guarded only does 35% of his normal damage to that target, so that's one healer doing the job of three because of all the tanks.
No shields allowed. You lack DPS in this group, so everyone has to contribute to damage to make up the difference. This group can be played multiple ways, so next time, I'll go over different ways to play this group makeup.