How to group contents in a PdfLightTable?

// Create a new PDF document instance
PdfDocument document = new PdfDocument();
#region Style for Table
// Create a border with a transparent color.
PdfPen borderPen = new PdfPen(Color.Black);
borderPen.Width = 1.0f;
// Assign the border pen to the table cell.
PdfCellStyle defStyle = new PdfCellStyle();
defStyle.BorderPen = borderPen;
PdfLightTableLayoutFormat format = new PdfLightTableLayoutFormat();
format.Layout = PdfLayoutType.Paginate;
#endregion
#region Functionality for the requirement
// Sort the DataTable
dataTable.DefaultView.Sort = "Column1 asc";
dataTable = dataTable.DefaultView.ToTable();
string lastValue = dataTable.Rows[0][0] as string;
DataTable tempDataTable = new DataTable();
tempDataTable = dataTable.Clone();
// Logic to separate the DataTable
foreach (DataRow row in dataTable.Rows)
{
    if (lastValue == row.ItemArray[0] as string)
    {
        tempDataTable.Rows.Add(row.ItemArray);
    }
    else
    {
        lastValue = row.ItemArray[0] as string;
        // Create the PdfLightTable
        PdfLightTable tblPDF = new PdfLightTable();
        tblPDF.Style.DefaultStyle = defStyle;
        tblPDF.Style.ShowHeader = true;
        tblPDF.Style.RepeatHeader = false;
         // Assign the data source
        tblPDF.DataSource = tempDataTable;
         // Draw the table
        tblPDF.Draw(document.Pages.Add(), 0, 0);
        tempDataTable = new DataTable();
        tempDataTable = dataTable.Clone();
    }
}
tempDataTable.Rows.Add(dataTable.Rows[dataTable.Rows.Count - 1].ItemArray);
PdfLightTable tblPDF1 = new PdfLightTable();
tblPDF1.Style.DefaultStyle = defStyle;
tblPDF1.Style.ShowHeader = true;
tblPDF1.Style.RepeatHeader = false;
tblPDF1.DataSource = tempDataTable;
tblPDF1.Draw(document.Pages.Add(), 0, 0);
#endregion
// Save the PDF document
document.Save("Sample1.pdf");
document.Close(true);
System.Diagnostics.Process.Start("Sample1.pdf");
this.Close();