Hi,
We have twin kids. A girl and a Boy. They will be 3 yrs in Nov. In some matters they are very adamant. Especially our daughter does not listen to a thing. If we tell her not to do some thing she would exactly do the same. It is very difficult to manage. They would not heed to our scoldings.
She puts fingers in mouth, always keeps standing on a chair never sits.
They also donot mix up with other children in our society. They would always cling to us. Even at the school they prefer to be close to each other.
Although it may not sound correct, you can request the school management to change their Division. In that way they will stop being dependent on each other and learn to mix with other children.
Siblings especially twins copy each other mannerisms. Changing the divisions will be helpful as then they will be in different classes and will not be able to copy each other. This will help them to make new friends also.