In a school setting, the links between the said groups are that of friendship, cooperation, and harmony.
Explanation:
School is a setting where there are young minds seeking growth of all sorts. For these minds to be on the right track, it is necessary that there are positive links between the smaller groups that are formed within the school.
The children from these groups learn from the links they share and grow up to possess good or bad relations with their counterparts. Hence, it is mandatory that the links that are formed at the school level itself are positive.