Introduction:
It always used to be 2 Necromacers dealing all the damage, but in this build, an Earth Elementalist takes over the role of the Spiteful Spirit Necromancer. This has 2 reasons. Earth Elementalists have great defence, making him a perfect tank, and Spiteful Spirit takes 2 seconds too cast, which is easily interupted, unlike the 1 second cast Spells from many Earth Magic spells. Of course, you still need a Monk, and a Minion Master has always been the perfect thing to take in Sorrow's Furnace.
The Monk:
Skills:
1. Reversal of Fortune
2. Mend Ailment
3. Blessed Signet
4. Life Barrier [Elite]
5. Life Bond
6. Life Attunement
7. Balthazar's Spirit
8. Divine Boon
Attributes:
Protection Prayers: 15
Divine Favor: 16
Short Guide:
Cast in these orders Life Barrier, Life Bond, Balthazar's Spirit and Life Attunement on the Elementalist, Balthazar's Spirit and Divine Boon on yourself and when you're in Grenth's Footprints also cast Life Barrier and Life Bond on the Necromancer. Simply heal with Reversal of Fortune and Mend Ailment (keep in mind that you heal alot more with Life Attunement), and use Blessed Signet whenever it's needed (which is mostly directly when it recharges).
The Earth Elementalist:
Skills:
1. Crystal Wave
2. Aftershock
3. Kinetic Armor
4. Armor of Earth
5. Obsidian Flesh [Elite]
6. Ward Against Elements
7. Ward Against Melee
8. Essence Bond
Attributes:
Earth Magic: 16
Energy Storage: 13
Short Guide:
The Elementalist is the main tank. He storms in first, and holds the Gear/Ural inside Sorrow's Furnace. Crystal Wave and Aftershock are your damage dealing skills. It's a bit less effective, but it works really well. You cast Essence Bond first after Life Barrier was cast on you, followed by the rest of the Monk's enchantments, since you won't be able to get Essence Bond back up during battle if it gets removed. Cast Kinetic Armor, Armor of Earth and Obsidian Flesh in that order and then aggro the enemies. Cast your Wards when you're next to them and then just cast Crystal Wave and Aftershock, and keep your enchantments up. Since you gain 2 Energy each hit, you shouldn't have much problems with Energy, especially against bigger groups.
The Minion Master:
Since there are many Minion Master builds, I'm not adding one. Take one you prefer, as long as it works, it should be fine. I prefer a N/E with Glyph of Renewal and Glyph of Lesser Energy myself, but as I said, it's a matter of preference

I hope you enjoyed my guide and 3-manning Sorrow's Furnace.
Max.