I had to do a similar thing on my 55k RTW. Although not all on one carrier, I did MEL-SIN-AMS on SQ, and in the middle SIN-BKK-SIN on TG. From AMS I had a nother 4 segments on different * carriers. In MEL they said that I could only check in for 5 segments at the most. We decided that the easiest point to have to recheck in would be at SIN where I had quite a few hours.

But when the CSR tried to tag my bags, she entered SIN as the final destination, but it wouldn't accept the SIN-BKK-LEGS. So I left my bags in SIN! Who needs an extra 2 legs for them to lose my bags?

I would've had them check you in to SIN, then transfer to HKG and back, without your bags, then back at SIN at the transfer desk get your BP for your flight to MEL, and have them tag your bags too.

goodo