Here is a little chart that I have prepared with information which we might use for parting the m-state elements:
 
 

		Dry M-state dissolves in
Element	ORME BP	Hydrochloric
Magnesium		Y
Calcium		Y
Cobalt		Y
Nickel		Y
Copper		Y
Ruthenium		Y
Rhodium	1066 C - 1250 C	Y
Palladium	Over 2700 C	Y
Silver	1800 C	Y
Rhenium		Y
Osmium		Y
Iridium	5400 C	N
Platinum		S
Gold	425 C - 600C	N
Mercury		Y

If you separate the gold, iridium and platinum out by dissolving the mix in HCl, then you can part the gold from this by heating the dry precipitate over 425 degrees. This would leave mostly iridium with a bit of platinum.

You can also take the dissolved m-state and re-precipitate it. The rhodium should be the first to come out of the dried precipitate when heated to 1066 degrees Celsius.

Hudson has a great deal more information on his chemical parting methods in his Australian patent.