Thanks, I will definitely post to the BA forum for any questions about household accounts.

My main question was just whether I could book the trip for both of us, using mileage from two separate accounts to cover each ticket, which you say is theoretically possible. I just need to figure out that it is possible, and we can be on the same itinerary and fly together. Especially since the RTW ticket, has an online booking through the trip planner. I am guessing if I call AA they may be able to tell me?

Planning to leave in 9 months and trying to figure this out so I know whether or not I need to go another route for mileage. Thanks!