Regarding routing of a AONE4 ticket, originating in HKG, going Asia - Europe - America - Australia - Asia.

On the way from SYD back to HKG, would it be allowed to go SYD - HKG (transfer less than 24 hours) - SGN - HKG (end).

Or would the whole trip immediately end when arriving in HKG, meaning no further segments allowed? I see no other reasonable OW connection SYD - SGN - HKG without going through HKG in between...

Thanks a lot!