That would be OK since o/w trips do not have a non-combinability clause. You'll pay thru the roof for both the o/w flights b'cos it's usually a Y or B fare instead of the lower class r/t fares (K, T, etc). Best bet: buy r/t tickets and discard the second halves. These "throw-away" itineraries are also a no-no in legacy airline fares... but are harder to track esp when you interline with another carrier to a destination not served by the main.