With Designer 7.x you will have to wrap each of the data sets on each of the pages in a subform and then with each of your barcodes, select the subform that you would like to collect data from.
Your life would be made much easier if you upgraded to Designer 8.x as you could create "collections" and then associate those collections to each of your barcodes.
With 3,000 characters of data you would more than likely be looking at 3 separate barcodes. The capacity does depend on the type of data your capturing but you should be covered with 3.
Lee