The disadvantage of reporting method is that if you line up casually, familiar people often stand closer and the groups will be separated. Because this kind of interference is not completely immediate. It might be better if you line up according to height and department.
By immediately, you mean that the people you want to group can't predict in advance and can't interfere with the grouping results in some way. For example, if you know the number to be reported in advance, you may think of countermeasures to obtain a favorable grouping method.
If it is your default grouping, find a playing card to represent some people, then shuffle more cards, then divide them into several groups of cards one by one, and then correspond to people.