We have a saved search which we call a batch report, similar to that you would have from a credit card processor with all the cash sales grouped by a custom field "Batch ID".  We populate the Batch ID per cash sale/csh refund in a different process.

We then create a vendor bill and populate the reference number (tranid) of the bill or bill credit enter with the Batch ID such that we can pay the vendor and tie the bill back to the specific group of cash sales that comprise the batch.

Sorry for the detail but thought it was important to provide context.