I will be flying from LHR to JFK next weekend. The flight is booked through AA but on a BA codeshare, so I am expecting to fly out of T5. I am in World Traveler Plus, and have an Admirals Club membership. I am only gold on AA.
I don't believe I will have access to any of the BA lounges based on this (please tell me I am wrong!). However, since I have Admirals Club, is there any way to get to T3 post security so I could use the AA lounge there?