Does anybody know exactly what rules apply to booking these tickets? You can book up to 6 segments and if there is something the system doesn't like you usually get the message "two departures from/to same country are not permitted".
But examples show this is clearly not correct, or maybe incomplete/inaccurate.
Even a simple return flight from London to Sydney for example involves two departures from Dubai, but this obviously is allowed.
Then I tried e.g.
FRA-DXB
DXB-SYD
SYD-CHC
MEL-SIN
SIN-DXB
DXB-FRA
but that is not allowed.
It looks like the exact rules are more complicated, maybe involving backtracking or equivalence within a zone like Asia-Pacific or something, but I find no documentation on this. Maybe there are some experts out there who know more?
Many thanks for any ideas!