. In a group of two or more people, must there always be at least two people who are acquainted with the same number of people within the group? Why

This must happen in order for group control to be maintained.

Explanation:

It is necessary that at least two people within a group know the number of members in that group to make sure that control of the group is maintained. In this way, these two people can manage the activities of the group based on their number of members, in addition to determining whether the group needs to be increased or decreased in order to reach their goals and complete their activities.

sounds good to me mate!