How can the automated boarding gates work that way when on separate PNRs? An authorized 4-person “trail” programmed in would mean that a non-priority boarding passenger just needs to follow most any individual with priority boarding and get in too. And if it works as suggested in the second sentence above for boarding but is limited to 4 “trailers” regardless of automated or manual boarding, then that is new and a negative cap for Star Golds traveling with say five family members (without all the same priority boarding group noted on the boarding passes).

IIRC, for some airlines even passengers all on the same PNR have at times been given different boarding pass group numbers/letters than some others on the same PNR.