I'm thinking you need to either engage the services of a brick and mortar travel agent, or call one of the websites' call centres, ask for the flights you want, and see what they can quote.

The thing to keep in mind is that Int'l flights are still often not sold "by the segment" like we are accustomed to with domestic/transborder flights. So be prepared for some sticker shock if a TA has to piece it together using one way fare rules on different airlines which do not have fares eligible for code-sharing.