[PvP] Looking for Tips on focusing targets as a Tank in the Feast

(4v4 Ranked feast) I play DRK and usually I go for the Melee who takes the attack buff together with my so we can burst him off and continue for their healer or ranged with the defensive buff. Is this correct to do or is it better to focus my CC on the enemy team's healer and spam my shield on my Melee or whoever else is focused ? Any tips are really welcome since I'm looking to get better.