I am AA PLAT and I want to have options so I would also like to have a *A elite level that will give me lounge access on international *A flights.

Which *A airline would be my best shot at getting a *A Gold match for my AA PLAT? Is it true that you can use the *A lounges on international flights even if your ticket is not from the airline (not even codeshare) you have your *Gold card from?

(used to be US Airways Chairman's but moved to OW and lost that... I still have a bunch of miles with US Airways but want to consider all options. My main interest is lounges, but SWUs are also a plus - e.g. AA EXP gives you 8, US Airways CH only gets you 2...)

Thanks!