Ardent Utility 6Battle Link
Your senses merge with your ally’s until you see things from all perspectives.
Minor Action Ranged 5
Target: Two allies you can see or you and one ally you can see
Effect: Until the end of the encounter, whenever the targets are within 5 squares of each other, neither grants combat advantage for being flanked unless both are flanked.
Published in Player's Handbook 3, page(s) 28.