Did multi-city not work? The challenge is that AUS is unlikely on the routing from ORD-HKG. If you were doing AUS-ORD <layover> -HKG then it would be easy.

Your best bet if the price for a multi-city is totally crazy might be to do an ORD-IAH-SFO-HKG and break the trip in IAH with an IAH-AUS-IAH round trip (could be on any airline). It's far more likely that you can route through a hub on your way to HKG than it is through AUS.