Yes, especially if a child is in need of true help. Group counseling and interventions, though they fail sometimes, sometimes work for people, including students. When it comes to the youth, we should be trying to protect them by any means necessary. If that means group counseling and interventions then so be it.
Yes, group counseling and intervention should be used in a school environment, because that way counselors and teachers could help more students in a smaller time. Also, sometimes what is most helpful to the student is to know that other students are going through the same thing as them. Group counseling can help solve problems.
Interventions are such a different situation to be in that they should be done in a more reserve and quite environment. Having a intervention in a school environment is way over the top and unnecessary and sort of violates the privacy of the individual infringing on their freedom and rights.
Unless a direct problem is being addressed between the parties involved then group counseling and intervention should not take place in the school environment. The primary purpose of a school is education, not mental health. I believe these services should be provided by the health care industry, not those employed in the education industry.