The IDLgrViewgroup::Add function method verifies that the added item is not an instance of the IDLgrScene or IDLgrViewgroup object. If it is not, IDLgrViewgroup:Add adds the object to the specified viewgroup.
Obj->[IDLgrViewgroup::]Add, Object [, POSITION=index]
An instance of an object or a list of objects. Objects which subclass IDLgrScene or IDLgrViewgroup can not be added (avoiding circularity constraints). All other objects are allowed.
Set this keyword equal to the zero-based index of the position within the container at which the new object should be placed.