Multiple reports in one Cystal Report.

I have 2 or more reports and I want to be able to open them in a single report. Let's call it the master report. In this report I want to open several reports, that are independent one to another. I'm using this code to generate the raports:

Code:

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Dim crDocument As New CrystalDecisions.CrystalReports.Engine.ReportDocument
Dim cmd As New OleDb.OleDbCommand
Dim da As New OleDb.OleDbDataAdapter
Dim dt As New DataTable

Dim crTemp As New crMyReport

cmd.CommandText = "SELECT * FROM myTable " & param
cmd.Connection = myDatabaseConnection
da.SelectCommand = cmd
da.Fill(dt)

crDocument = crTemp
crDocument.Load("crMyReport.rpt")
crDocument.Database.Tables("command").SetDataSource(dt)

rptViewer.DisplayGroupTree = False
rptViewer.ShowGroupTreeButton = False


rptViewer.ReportSource = Nothing
rptViewer.ReportSource = crDocument
Me.Show()
rptViewer.Show()

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With this code I rewrite the datasource of the raport, and I can filter the query by the 'param' variable in the query.

After setting the datasource of the report i can save the raport:

Code:

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crDocument.ExportToDisk(CrystalDecisions.[Shared].ExportFormatType.RichText, "C:\temp.rtf")

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into rtf, pdf, etc. I want to append more of these reports into a master empty report. Or load these reports as subreports into a master empty report. I've tried everything , researched online, but didn't managed to find any guides. Can anyone help me?