They will all be played from 13-24 June with the three group winners and best secondplaced side progressing to Lord's, where two semi-finals and the final will be played on 19 July.
As well as needing to win their final two games, the Ospreys are relying on the second-placed Cardiff Blues defeating leaders Leinster on Friday for the west Glamorgan side tobe able to claim the title for the second time.