If I understand correctly, you want to filter the sample barcode from the main report even though this field is not present in the main report?

If that's the issue, you can simply add a parameter to the main report to allow you specify which sample barcode values should be present. You don't necessarily have to use that parameter in the query for the main report. When linking to the subreport, be sure to include the sample barcode value as a parameter mapping from main report to subreport.

If this doesn't answer your question, perhaps you could include some code or screenshots for clarification?