I believe they have an I-fare, but (1) requires 7-nights minimum (2) valid on CX 888/889 only (i.e. via YVR both ways), and yet it's still ~HKD 60k, substantially more expensive than other airlines that's maybe half the price and with also one stop, or just similar in price with DONE3 which doesn't require any minimum stay out of HKG and allows travel on the nonstops (and JFK-YVR-HKG is just similar in time vs. JFK-LHR-HKG) - so you might as well do HKG-JFK-LHR-HKG rather than HKG-YVR-JFK-YVR-HKG...