to kill the first gatekeeper quickly is have everyone stay at the door and crouch, avoid any HobGoblins fire and have everyone shoot the living crap outta it. To kill the ones in the portal you need to do Mars(Left side) First with two maybe three people. Then the relic holder goes into the second portal with the second soon to be relic holder, but as they get the second have two guard the portal and then have one protect the Conflux (the middle) or have one guard portal, two guard the middle, whichever works for you. Thats how I've done it with the many Raid teams I joined Hope it helps