I have booked a flight on JAC to KOJ (from Yakushima). I'd like to book another ticket onto Osaka. I'm wondering 1) if they'll be able to combine my reservation (really just transfer my bag) and 2) how much connection time I'll need (particularly if they're unable to transfer the bag).

I called JAL in the US and the agent said he had no idea has JAC was a completely separate airline, and I'd have to call Japan. JAL's website does mention minimum connection time between the two airlines (20 minutes) but I'm guessing that's for flights on the same reservation.

Thanks in advance!