Question 95
$3n$ ($n$ is a positive integer) girl students took part in a summer camp. There were three girl students to be on duty every day. When the summer camp ended, it was found that any two of the $3n$ girl students had just one time to be on duty on the same day.
(1) When $n = 3$, is there any arrangement satisfying the requirement above? Prove your conclusion.
(1) When $n = 3$, is there any arrangement satisfying the requirement above? Prove your conclusion.