Multiple ZRE1 against ZOR linkages

Dear Gurus

i am handling returns in a company, i wan to prepare report of particular invoice volume against return volume of that invoice. i want to prepare report monthly basis and that may possible either i have to show document flow for all ZRE1 mannually or have to track each invoice physically. please suggest if any othere way to make it eassy, we are not entering invoice number in referance of ZRE1 while punching ZRE1.

Example

(222) ZOR's invoice number (123456) having 10 SKU amounting 1000

customer returned 3 sku amounting 700 - now i prepare ZRE1 (999) for - (123456) invoice

i want prepare report that show 123456 invoice is supplied with Amount of 1000 and customer returned amount 700 so 70% of invoice no 123456 is returned by customer,