Members of the 8 groups:

Group 1: 13, 18, 23, 39, 42 Group leader: 23
Group 2: 10, 17, 27, 28, 33 Group leader: 17
Group 3: 4, 9, 14, 19, 32 Group leader: 9
Group 4: 7, 26, 29, 38, 41 Group leader: 26
Group 5: 1, 3, 20, 36, 40, 43 Group leader: 40
Group 6: 5, 11, 12, 16, 30, 34 Group leader: 30
Group 7: 6, 8, 22, 24, 25, 35 Group leader: 6
Group 8: 2, 15, 21, 31, 37 Group leader: 31