Modify the MARC record import screen such that each imported record has a check box next to it (checked by default). If there are any records we do not want to be imported, we can uncheck the box. When we select “Import this batch into the catalog”, only the checked items would be imported. The unchecked items would remain in the reservoir.
This functionality would be similar to the Batch Item Modification tool (batchMod.pl), which displays a list of items that a user can select/deselect. The tool only modifies selected items.