I don't think there is anyway of doing that. In any case it wouldn't be for BA to resolve it would be for the airline of your next segment, I guess either US or AA.

This re-routing will be made on what is available and what gets you to your destination with minimum delay. I would suggest its definitely good to have an idea of a re-routing and certainly suggest it, if the agent does not. I've done this before when I preferred a DUS connection to CDG.

If there is a direct connection later in the day that would be the first option.