Collection sub feature in Bentley Map

Does Bentley Map allow creating sub feature (not primary feature) which is a collection feature? I see, taht it is not possible in Geospatial Administrator. When I create XLM myself (in notepad i.e.), then Map seems to work fine until I try to create (in VBA) a component of such a collection sub feature. At that moment I get an error in ApplyAttributeChanges function (VBA) of primary feature after creating any component of such a collection sub feature.

Component path just before error is as follows: myMainFeature/mySubFeature_Collection/mySubFeature (GetPathFromRoot function).

Here is example VBA code fragment I expected to work:

‘ myMainFeature is already created, mySubFeature is a collection-polygon sub feature, myGeometry is a shape element
Private Sub Add_mySubFeature(myGeometry As ShapeElement)
    Dim mySubFeature_Collection As New xft.Feature
    mySubFeature_Collection.Name = "mySubFeature_Collection"
    mySubFeature_Collection.SetParentFeature myMainFeature
    Dim mySubFeature As New xft.Feature
    mySubFeature.Name = mySubFeature.GetFeatureDefinition.CollectionName
    mySubFeature.SetParentFeature mySubFeature_Collection
    mySubFeature.Geometry = myGeometry
    myMainFeature.ApplyAttributeChanges '(here error raises)
    myMainFeature.Write False
    myMainFeature.Display msdDrawingModeNormal
End Sub