Quick little question about Hoard!

[Wulffmeister]

Two days ago, i was in a round 'o munchkin, where we encountered a little trouble, where the table overruled what i thought was correct.

Now for the question:
Player A is against a monster, but can't defeat it alone.
Player B comes in to assist, and claims one treasure, first pick as reward.
Four Treasure are drawn, Hoard! being one of them.
Player B grabs x treasure card, and player A gets the 3 other, Hoard! being one of them.
Now Hoard! says to played as soon as it's picked up. Would that mean, Hoard! will only be played once player A get's it on his hand, and thereby gets another 3 treasure, or would it be played when it reach the table, so the treasures from Hoard would also be available for player B to choose from?