Originally Posted by
kyanar
Impossible. NZ doesn't fly to TXL, and they have no partnership with BA. BA also being a member of OneWorld, NZ (a StarAlliance carrier) cannot ticket you through the alliance either.
Why do you think this is impossible? A travel agent can certainly pull together an itinerary that includes non-alliance or non-cooperation partner airlines. You might not be able to do it online.
OP. Try using Matrix ITA to see if there is a fare per the example below. If you can't find an OTA, then a decent 'bricks and mortar' TA should able to pull it together.