Ask the AirNZ staff to 'TCP' the bookings (The Complete Party aka To Complete Party). This provides mutual notes in each PNR and a system link of some (basic) kind - but that is about it. Some stuff on TCP: https://servicehub.amadeus.com/c/por...p-pnr-cryptic-

Wife and I have same issue at year's end as we fly outbound together, but she is away 2 weeks longer. So we have 2 separate PNRs, which have been associated by TCP. I'll be interested to see if the system sees her as travelling with a GE (me) regarding her gifted RU.