How to export multiple WinForms GridGroupingControl data into a single PDF file?

private void button1_Click(object sender, EventArgs e)
{
    GridPDFConverter pdfConvertor = new GridPDFConverter();
 
    //Default is None. So, merge mode must be set.
    pdfConvertor.PdfMergeMode = GridPDFConverter.MergeMode.MergeAfter;
 
    //Export 1st Grid.
    pdfConvertor.ExportToPdf(gridDoc, this.gridGroupingControl1.TableControl);
 
    //Export 2nd & 3rd grids.
    pdfConvertor.ExportToPdfWithMerge(ref gridDoc, this.gridGroupingControl2.TableControl);
    pdfConvertor.ExportToPdfWithMerge(ref gridDoc, this.gridGroupingControl3.TableControl);
}

Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button1.Click
     Dim pdfConvertor As New GridPDFConverter()
 
     'Default is None. So, merge mode must be set.
     pdfConvertor.PdfMergeMode = GridPDFConverter.MergeMode.MergeAfter
 
     ‘Export 1st Grid.
     pdfConvertor.ExportToPdf(gridDoc, Me.gridGroupingControl1.TableControl)
 
     ‘Export 2nd & 3rd grids.
     pdfConvertor.ExportToPdfWithMerge(gridDoc, Me.gridGroupingControl2.TableControl)
     pdfConvertor.ExportToPdfWithMerge(gridDoc, Me.gridGroupingControl3.TableControl)
End Sub