Apologies if this is covered elsewhere but am trying to book a RTW in F from GRU (and thereafter CPT/DPS/SYD/AKL/SCL/GRU) and would appreciate any advice as to how to avoid
1) Eccentric routings (eg F GRU/CPT offered GRU/MAD/LHR/CPT with no F GRU/MAD, obviously
2) Mysterious warning messages ie 'you must be booked on this carrier to select this segment - please choose another flight'


Any tips greatly appreciated.