Hello! I read today, that there´s a possibility to exchange miles between different Mile programes over the HiltonHH program. Normally I save my miles with United Mileage Plus but now I have to go with British Airways and Quantas who are members of oneworld I think. How to bring these miles ti my Mileage Plus program? Do I have to be member of oneworld too or is it O.K. to be member of Hilton and then transfer them to Mileage Plus!? How does it it and is it possible?

Thank you!!