Final answer:
The counselor must first contact each student's parent or guardian to discuss the social-skills group's purpose and ask for permission to include their child in the group.
Step-by-step explanation:
The first step a counselor should take when establishing a social-skills group to resolve a dispute among sixth-grade students is to contact each student's parent or guardian to discuss the purpose of the group and to request permission for the student to attend. This not only ensures that parents are informed and involved in the decision-making process regarding their children's education and social development but also adheres to ethical and legal standards within the school setting. Before any intervention involving minors begins, parental or guardian consent is typically required, especially for programs that fall outside of the normal curriculum.