It depends on the policies and procedures at each local airport authorities. Some airports may not accept passengers who display all Passbook Boarding Passes with their companions on one device. At the security checkpoint, they will be advised to return to check-in counters to re-print their boarding passes.
We advise you to send and store the Passbook-enabled Mobile Boarding Pass to each device, and so each device will only display one Boarding Pass at the airport. If any of the companions does not have any mobile devices or the relevant iOS, they are encouraged to use the Self Print Boarding Pass after checking in online, or send the mobile boarding pass via SMS or email, as an alternative.
Mobile Check-in users can only add the boarding pass into Passbook when the booking contains one passenger only.