I was turn down by the check in agent in SIN, and will have to wait for my colleague . The agent told us that our tickets was booked as GV2 promo fare. We have to check in together ,taking same flights together on both legs. SO theoretically, it depends on the fare condition. Separating iterinary is one thing ( I have separate eticket only on my name) but apparently the airline system will ask for both passenger before it generate boarding pass