ok, so i've done a bit more research and come changed my itinery a bit :

man - xlhr - sin
sin - xhkg - nrt
nrt - hkg
hkg - sfo
sfo - ord
ord - xlhr - dub
dub - xlhr - man

question 1 : does this work? i would like to purchase a business class oneworld explorer covering 3 continents.

question 2 : could i do :

man-xlhr-bkk-sin or man-xlhr-xsin-dps-sin instead of man-xlhr-sin

sfo-hnl-xlax-ord instead of sfo-ord

ord-lhr-dub instead of ord-xlhr-dub

thanks...dx