VB.NET Excel - How to group rows and columns

  
' Group rows
osheet.Range("A1" , "A20" ).Group(True, , , )
' Group columns
osheet.Range("D1", "G1").EntireColumn.Group(True, , , )


-- colapse groups
'osheet.Columns("G").OutlineLevel = 1.0
osheet.Outline.ShowLevels(ColumnLevels:=1)