Hi Marcia.Maybe you could drop another instance of your BO in your form and use it as your BrowseDialog's BusinessObjectToPopulate. Then in the BrowseDialogClosed method, if a OK was pressed by the user, you could filter your populated BO as needed and use the CopyDataFrom to copy the records to your primary BO.
As for how to filter the duplicated records, you could add a new Column to your BO for that purpose.
Private Sub MyBO_CurrentDataTableInitialized() Handles MyBO.CurrentDataTableInitialized
If Me.CurrentDataTable.Columns.Contains("myb_Duplicated") = False Then
Me.CurrentDataTable.Columns.Add("myb_Duplicated", System.Type.GetType("System.Boolean"))
End If
End Sub
(You probably need to create the custom property for that column too)
Then you could go through all your records testing for duplicated ones, and flaging then as so. Filter on that flag before the CopyDataFrom.
Hope I could make some sense...