Record grand slam winner Rafael Nadal will lead Spain against hosts Australia and Britain in the maiden edition of the mixed team United Cup tournament and women’s world number one Iga Swiatek of Poland will be up against Switzerland and a qualifier. The group stage for the December 29-January 8 tournament featuring 18 teams was drawn on Thursday in Sydney, with teams seeded based on their best women’s and men’s players. This saw Greece with men’s number three Stefanos Tsitsipas and women’s number six Maria Sakkari seeded top and drawn to face Belgium and a qualifier in Group A. The group will…