How to group contents in a PdfLightTable?

 
//Create new PDF document instance
PdfDocument document = new PdfDocument();
            
#region Style for Table
            
// Creating Border with transparent color.
 PdfPen borderPen = new PdfPen(Color.Black);
 borderPen.Width = 1.0f;
 
// Assigning the border pen to table cell.
PdfCellStyle defStyle = new PdfCellStyle();
defStyle.BorderPen = borderPen;
 
PdfLightTableLayoutFormat format = new PdfLightTableLayoutFormat();
format.Layout = PdfLayoutType.Paginate;
#endregion
 
#region Functionality for the requirement
//Sorting the Data table
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 seperate the Data table
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;
         //Creating the PdfLightTAble
         PdfLightTable tblPDF = new PdfLightTable();
         tblPDF.Style.DefaultStyle = defStyle;
         tblPDF.Style.ShowHeader = true;
         tblPDF.Style.RepeatHeader = false;
                   
         //Assigning the Data source
          tblPDF.DataSource = tempDataTable;
                   
         //Drawing 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
 
//Saving the PDF document
document.Save("Sample1.pdf");
document.Close(true);
System.Diagnostics.Process.Start("Sample1.pdf");
this.Close();