I have been told otherwise regarding merging PNRs as per the EXP desk. Its apparently a royal PIA and most will say they can't/refuse to do it. But apparently it can be done. Admittedly via a lot of manual work.

Have three people flying on $3500 int'l tickets (coach down, business back). Two EXPs and a non-status pax. Want to use VIPs on the way down. Also want to use Costco GCs but you can't get more than 8 of them on one PNR - thus no 10% discount above $2400. If I separate everyone, I get a discount of $720. If I leave the non-status pax on the record with one of the EXPs, I only get a $480 discount. If I separate them, the non-status pax doesn't get the benefit of EXP status on the waitlist.