wpf listcollectionview grouping by multiple columns. Only view

public class ViewModel {
  private readonly ListCollectionView _collectionView;
  public ViewModel() {
    _collectionView = new ListCollectionView(myList);
    _collectionView.GroupDescriptions.Add(new PropertyGroupDescription("Name"));
    _collectionView.GroupDescriptions.Add(new PropertyGroupDescription("Age"));
  }
  public IEnumerable MyCollectionView {
    get {
      return _collectionView;
    }
  }
}