Rowspan style in RadGrid view

I've set the row span style, the selection is applied only for the single cell but I need it for the whole merged cell. I've added the code for your reference. Please check image & do the needful.

code :

MergeVertically(Me.rdgvRGrid, New Integer() {0, 1})

  Private Sub MergeVertically(radGridView As RadGridView, columnIndexes As Integer())
        Dim Prev As GridViewRowInfo = Nothing
        For Each item As GridViewRowInfo In radGridView.Rows
            If Prev IsNot Nothing Then
                Dim firstCellText As String = String.Empty
                Dim secondCellText As String = String.Empty

                For Each As Integer In columnIndexes
                    Dim firstCell As GridViewCellInfo = Prev.Cells(i)
                    Dim secondCell As GridViewCellInfo = item.Cells(i)

                    firstCellText = (If(firstCell IsNot Nothing AndAlso firstCell.Value IsNot Nothing, firstCell.Value.ToString(), String.Empty))
                    secondCellText = (If(secondCell IsNot Nothing AndAlso secondCell.Value IsNot Nothing, secondCell.Value.ToString(), String.Empty))

                    setCellBorders(firstCell, Color.FromArgb(209, 225, 245))
                    setCellBorders(secondCell, Color.FromArgb(209, 225, 245))

                    If firstCellText = secondCellText Then
                        firstCell.Style.BorderBottomColor = Color.White
                        secondCell.Style.BorderTopColor = Color.White
                        secondCell.Style.ForeColor = Color.Transparent
                    Else
                        secondCell.Style.ForeColor = Color.Black
                        Prev = item
                        Exit For
                    End If
                Next
            Else
                Prev = item
            End If
        Next
    End Sub

    Private Sub setCellBorders(cell As GridViewCellInfo, color As Color)
        cell.Style.CustomizeBorder = True
        cell.Style.BorderBoxStyle = Telerik.WinControls.BorderBoxStyle.FourBorders
        cell.Style.BorderLeftColor = color
        cell.Style.BorderRightColor = color
        cell.Style.BorderBottomColor = color
        If cell.Style.BorderTopColor <> Color.Transparent Then
            cell.Style.BorderTopColor = color
        End If
    End Sub