Referencing Main Report Data In Subreport

[Babs827]

Ok I'm trying to find data in a subreport but I only want to sort through the records that are contained in the main report. For example, if my main report shows the data below when run, how can I do a subreport that will limit the records to only the unique identifiers that appear on the main report?

Unique Identifier
-------------------
12345
24321
43213
25332

Thanks,
Babs827