User blog:Martialmaniac/Bill, Sayird, and Kurton's true allegiance

We totally missed it because of the unofficial translation, but in the official one, Bill confesses that he and the other two Hunters working for Oito are part of Beyond's Expedition Team. The confusion is because of what Bill tells Kurapika in Japanese:

「―――――という訳で 本来の目的はビヨンド氏と共に暗黒大陸を探検する事だが それを理由に 途中の任務を蔑ろにはしない！」

Long story short, there is no subject, so it could be Bill talking about the Zodiacs' objective or his own. However, in the page before that, Kurapika talks about Bill's true mission:

ハンターならば２層の警備に回してもらえるだろう 君達の本当の任務には支障が出ないはず

So Kurapika was already certain that Bill & co. were working for Beyond and Pariston, but he was not sure what their role was, and Bill explains it to him. I'll add them to the Expedition Team right away.