If you lead a booking as an elite then the baggage etc is made available to all pax on the booking (up to 8 people).

If you are a named customer on a group booking created by a TA or someone else or a larger group than 8, then if you can get the PNR, you can add your card number in MMB and get your individual benefits, but this doesn't apply to anyone else in the group.

Your partner would need to find out the PNR from whoever is managing the group booking in this case..