Originally Posted by
natbread
If you're all on CX or oneworld - inform checkin at point of origin that you have a connecting flight on a different ticket and they should be able to link the bookings and check you in for your onward flight from BKK
As noted at the link above, if the first flight is on CX then the onward flight can be on any of their partner airlines. And "partner" here means interline partner, which is a much longer list than just the oneworld airlines. (It's more or less every traditional (i.e. not LCC) airline).