private void MergeTwoReports() {
    // Create the 1st report and generate its document.
    XtraReport1 report1 = new XtraReport1();
    report1.CreateDocument();

    // Create the 2nd report and generate its document.
    XtraReport2 report2 = new XtraReport2();
    report2.CreateDocument();

    // Merge pages of two reports, page-by-page.
    int minPageCount = Math.Min(report1.Pages.Count, report2.Pages.Count);
    for (int i = 0; i < minPageCount; i++) {
        report1.Pages.Insert(i * 2 + 1, report2.Pages[i]);
    }
    if (report2.Pages.Count != minPageCount) {
        for (int i = minPageCount; i < report2.Pages.Count; i++) {
            report1.Pages.Add(report2.Pages[i]);
        }
    }

    // Reset all page numbers in the resulting document.
    report1.PrintingSystem.ContinuousPageNumbering = true;

    // Show the Print Preview form.
    report1.ShowPreviewDialog();
}

Private Sub MergeTwoReports()
    ' Create the 1st report and generate its document.
    Dim report1 As New XtraReport1()
    report1.CreateDocument()

    ' Create the 2nd report and generate its document.
    Dim report2 As New XtraReport2()
    report2.CreateDocument()

    ' Merge pages of two reports, page-by-page.
    Dim minPageCount As Integer = Math.Min(report1.Pages.Count, report2.Pages.Count)
    For i As Integer = 0 To minPageCount - 1
        report1.Pages.Insert(i * 2 + 1, report2.Pages(i))
    Next i
    If report2.Pages.Count <> minPageCount Then
        For i As Integer = minPageCount To report2.Pages.Count - 1
            report1.Pages.Add(report2.Pages(i))
        Next i
    End If

    ' Reset all page numbers in the resulting document.
    report1.PrintingSystem.ContinuousPageNumbering = True

    ' Show the Print Preview form.
    report1.ShowPreviewDialog()
End Sub