I suppose the only thing to do would be to ask each state board of medicine.
If they accept Royal College of GP in Canada training, then why not Royal College of Australia considering that the American Board of FP recognizes the training as equivalent!
http://en.wikipedia.org/wiki/American_Board_of_Family_Medicine
Canadian programs are not accredited by ACGME either. They simply recognise the training by an "agreement" that they are equal, I don't see why the state boards can't have this same agreement with Australia seeing as they are equivalent programs in 1st world english speaking countries, etc, etc. (and with backing from the American Board of FP) If they say no, ask why not! Then ask them to demonstrate how the Australian programs are deficient compared to the Canadian programs
You'd think they'd want as many FP/GPs as they can get...