You gear up and kill them in 2-3 hits with level appropriate weapons. Brute should be dodged, shaman focused down first. Start in with the bow if possible, fire arrows do wonders against tree people.
Make sure you are well fed and rested for the buffs to regen and stamina.
Multiplayer buffs the enemies so its only easier in regards to someone can play a tank roll while someone else does a dps focus, and you can rotate if you are coordinated.