Opinions are divided as to whether troublesome school students should be separated from other students. In my opinion, it would be definitely make the matters worse if the student are isolated.
Imaging picture in a prison, grouping trouble people together will cause of even more trouble because these prisoners always conspire together for prison's rules. Their reaction is as if they are a rebel and rule is definitely wrong. If we use this principle to children in school. The consequence is, children will be very difficult to control. Moreover, kids' development affects mainly from their friend both positive and negative habits. Because in any ecosystem, humans always learn characteristics from other, they copy what they see from each other, it will be even worse if the model is stubborn students. Nevertheless, teachers are just ordinary people. They have emotions, needs, hates and etc. When teachers assign to teach specific group of children especially a trouble group, teachers will lack of motivation to teach these people. Finally, these students may not be taught properly.
On the other way, if troublesome children are followed by the right way and sending them into a proper ecosystem. There has been a lot of evidences in many schools, at some age, having a good grade is what people admire. So that it is more likely that they will turn back to be normal when they grow up in the future.
In conclusion, I believe that things would get worse if difficult students are isolated from other students.