What I usually did (but is slightly to much effort according some for what it's worth) is put this data in a table in the database I work in, then make a impromptu report only selecting the column with those codes, save the report. When you then go to your original report you can say in the filter that c (your codes in the report) can not be in dataset. You then get a window where you can select the new impromptu report you just generated earlier and chose the column in that report.
I know, a big way around but it works perfectly :s