Just a note for others- I wasn't seeing J availability on an EY flight AMM-AUH even though I had availability on AUH-SYD, then searched AMM-SYD and on exact same flights as married segments I was able to pull up 4 J seats.
Called AA rep and at first they said their was no availability, but I convinced her finally to search as a married segment and she was able to find and hold the awards for me.