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Outside of the Avios airlines (British Airways, Iberia, Aer Lingus & Qantas) there isn’t inter-airline miles transfer for OneWorld alliance.
However you can use those points to book flights on American Airlines, assuming there is availability.
Once you move bank points to a travel partner those miles are to be used within that program.
So yes you’d need to book American Airlines flights via Qantas.
Be sure to verify the award space before transferring.