There are about 80 people in a dozen departments, and there are only about five or six people in one department. A dozen departments can be grouped according to ABCD. One group represents a department, and the same group evades when drawing lots. That is, a person is drawn from Part A, and his opponent plays against a person from Part B (Part B is also a lottery). Try not to let all departments a hit b, a hit c, d, e and so on.
The winner of the second round of elimination will draw lots again, which can avoid the early meeting of employees in the same department.