Rasools Are For The Entire Humanity But Only An Adalat For Their Own Nation
Their Hidayat/Teachings are universal like belief in God, Belief in hereafter etc.. Quran has asserted on a number of occasions that all the prophets brought the same message. Direct addressees of a Prophet may vary but the nature of their teachings are for all mankind. This serves both purposes i.e. itmam-e-hidayah and itmam-e-hujjat for the rest of mankind. Please also see these comments of Ghamidi Sahab in the video below from 54:55 to 1:00:11 https://youtu.be/eNJn0iZfZMk?t=3295