cdm/src/main/java/ucar/nc2/Structure.java
@Override
  public void setParentGroup(Group group) {
    if (isImmutable())
        throw new IllegalStateException("Cant modify");
    super.setParentGroup(group);
    if(members != null)
    {
        for (Variable v : members) {
          v.setParentGroup(group);
        }
    }
  }
@Override
  public void setParentGroup(Group group) {
    if (isImmutable())
        throw new IllegalStateException("Cant modify");
    super.setParentGroup(group);
    if(members != null)
    {
        for (Variable v : members) {
          v.setParentGroup(group);
        }
    }
  }
Set the parent group of this Structure, and all member variables.