I think Moondog is theoretically correct. And usually works for inbound to the USA--I've done it myself. However, coming inbound to China, I don't hold out hope that Xiamen Airlines will do anything except rip off the CO-placed tags, put on their own tags, and charge for excess weight.

Unlike the USA, where you can clear Customs at port of entry and then (if bags are tagged through) place them immediately on the luggage belt for domestic connections without going back to a check-in desk...China has no such provision. No way to avoid that Xiamen Airlines check-in desk that I can see.