It is possible to interview at 2 places but can pose problems. What happens is the first airline who decides they want to hire you must submit to the CAAC to do a license background check. The first one who submits this to the CAAC ties up this license and passport and for the time being essentially owns you. If the second company decides they want you then there has to be a negotiation for your license ie a few red envelopes are passed to move you. Switching from one airline to another is also possible but you must be released by the owning airline. It is easier to do this at the end of a 3 year contract than trying it while you are still under contract. In China anything is possible if the gaining airline wants it bad enough but the best thing to do is try and choose an airline where you might want to remain for awhile ie do your homework. China is notorious for hiring you as a Captain on these widebody contracts and then only using you as essentially a Cruise Captain. The CS non type rated contracts are really bad for this on the Boeing fleet. The airbus is a little better but you will NOT fly as the PIC you will be a glorified IRO paid as a Captain but never signing for the airplane or being able to make a landing without the true PIC in the other seat.