Setting aside for a moment the issue of it not being proper for the OP to use a rail pass, there's also the issue of whether or not you could actually accomplish it. If the OP had a friend coming in that would NOT be traveling with them, then it's probable that they'd get away with it. But if the OP and the "Temporary Visitor" friend plan to travel together, there's no way that the friend is going to be able to activate two exchange orders for two passes with simultaneous validity during the same transaction. What is unknown (at least to me) is whether the friend could activate each pass separately (at separate times and JR offices) for simultaneous validity. It all depends on whether the passport number is entered into a JR computer at the time the exchange order is processed - if so, then it's probable that they'll catch this situation even if the friend attempts the exchanges at different times.