Adds an ADSI object to an existing group.
HRESULT IADsGroup::Add(
  BSTR bstrNewItem  //ADsPath of the object to add
);
 This method supports the standard return values E_FAIL and E_UNEXPECTED, as well as the following:
  Windows NT:  Use version 4.0 and later. 
  Windows CE:  Unsupported.
  Header: Declared in iads.h.
IADsMembers, ADSI Group Object, ADSI Members Object