I booked NBO-LHR-LAX-STL in business for myself and a friend. It's an AA ticket, but on NBO-LHR-LAX legs it's operated by BA. I booked us as two separate reservations because their return from STL to Europe is at a different date from my STL to Europe. On the BA flights I can pick seats in business for free (due to Oneworld Emerald), but for them it's $150-200 for each leg on BA. On the AA flight together (LAX-STL) we can select seats together no problem.

I know with AA I can link my executive platinum status to someone else on a different PNR/reservation on the same flights with me. They get the same MCE benefits, etc... Is there anyway to do this on an AA ticket for the partner flights when they are booked on separate PNRs? I tried called AA and BA once so far and had no success, but maybe it's a hang up call again situation? Wondering if anyone has made this work...