According to the Oneworld timetable, there's daily service EZE-UIO and v.v. on XL (Lan Ecuador) - two stops but a through flight number, hence one xONEx segment (shown as LA 1446/1447.) Then IB flies UIO-MAD nonstop, so an itinerary e.g. (AKL/SYD)-SCL-GRU-EZE-UIO-MAD-LHR would be kosher.