Complex sentence: Australia considers the All Blacks (New Zealand) to be their greatest rivals; with whom they have contested the Bledisloe Cup since 1932, however the Wallabies have won fewer than 30% of their encounters against their trans-Tasman opponents.
Split into simpler sentences: Australia considers the All Blacks (New Zealand) to be their greatest rivals, with whom they have contested the Bledisloe Cup since 1932. The Wallabies have won less than 30 per cent of their encounters against their trans-Tasman opponents.