how to merge or display two different objects of dataset in vb.net?

Dim obj As CRDataset = New CRDataset
  Dim obj1 As CRDataset = New CRDataset

Dim balrow As DataRow = obj.Tables("DB_COM").NewRow()//obj for one group of value
                           balrow("fbankname") = gbankname
                           balrow("fbranchname") = gbranchname
                           balrow("fusername") = Guser
                           balrow("fworkstation") = worknode
                           balrow("fserverdt") = serverdt
                           Dim gpt As String = Format(fromdate.Value, "dd/MM/yyyy")
                           balrow("fdate") = gpt
                           balrow("fmainhead1") = fmainhead1
                           If OPENSTATE = "1" Or OPENSTATE1 = "1" Then
                               balrow("fcrtot") = CRBAL
                               balrow("fglhead") = fglhead
                               CRBAL = 0
                           End If
                           'If OPENSTATE1 = "2" And fglhead1 <> readglhead Or OPENSTATE = "2" And fglhead1 <> readglhead Then
                           '    balrow("fdrtot") = DRBAL
                           '    balrow("fglcode") = fglhead1
                           '    readglhead = fglhead1
                           'End If
                           obj.Tables("DB_COM").Rows.Add(balrow)
                           If OPENSTATE1 = "2" And fglhead1 <> readglhead Or OPENSTATE = "2" And fglhead1 <> readglhead Then
                               Dim alrow As DataRow = obj1.Tables("DB_COM").NewRow()//obj1 for another group of value
                               alrow("fmainhead2") = fmainhead2
                               alrow("fdrtot") = DRBAL
                               alrow("fglcode") = fglhead1
                               readglhead = fglhead1
                               obj1.Tables("DB_COM").Rows.Add(alrow)
                           End If

Dim cr As New ReportDocument
       cr = New BALANCESHEET//crystall report

       cr.SetDataSource(obj.Tables("DB_COM"))//set datasource obj
 cr.SetDataSource(obj1.Tables("DB_COM"))//set datasource obj1
       repview.CrystalReportViewer1.ReportSource = cr
       repview.Show()