I'm not quite sure if I'm posting this in the right place, so if not, please feel free to shift it elsewhere!

I was wondering if someone could advise me. I have a return flight from Milan to Brisbane return, and was hoping to allocate the points in one direction to my Qantas FF account, and then the other way to my AA account. Does anyone know if this is possible? Is it just a matter of contacting Qantas and changing the number on the account after the first leg is completed?

Thanks for your help!! ^