Seems I'll be using multiple carriers of *A more (US Air, United, Swiss, and Air China).

Right now I really only fly Lufthansa on *A. How will mileage be assessed? Will I still qualify for XYZ level if all the miles are split between the 5 carriers? And which carrier would I get the actual card from? (Right now I have the Lufthansa card) Will I lose any benefits? What about lounge access?

I'm moving and my role is changing, so I won't be flying out of JFK much anymore.

Thanks.