I think RAW is about 90% there. Key is no use of the word of 'each'. There's just the argument otherwise. There's a host of powers that do very, very odd things if you read it otherwise. Including powers that apparently only end if any ally, specific, hits a target 3 times, but as long as no single ally hits more than twice, all good. Look at Deathguide's Sanction or Spirit Ocean to compare...For me, it is that very "any" which opens up the second reading. I agree that, RAI, one single ally is probably the correct ruling. But RAW? Hard to say with such screwy wording!