Jet Airways website says it has an interline agreemnt with NWA via Mumbai.

My friend is flying Jet from MAA-SIN and connecting on to NWA from SIN to Tokyo onward to USA on a separate ticket.

Is it possible for him to interline his bags from 9W to NW especially when there are two tickets involved. Other wise he has to clear immi/custom and can't come back in since the NW counter will not open until next day morning for him to check his bags in.

Any suggestions? Thx.