Search for duplicate sales invoice numbers and purchase order numbers, backorders

[ELVS]

Hello,

I would really like to have a search function for finding duplicate sales invoice numbers and purchase order numbers. 

The reason is that when a back order is created (either sales or purchase), we retain the original invoice/PO as this is the ONLY way to link it to the original order. We add a suffix for each back order eg -1, -2, -3 to identify that it is the 1st, 2nd, 3rd (sometimes up to 7th!) backorder relating to the original. I have voted for another idea post that suggests an option for this to be automated....

However, currently, this is a manual task and it sometimes gets forgotten.

Having duplicate invoice or PO numbers creates a big problem for many companies, especially those that use automation for applying payments.

We would like to be able to search for duplicates during our EOM procedures prior to sending out statements and remittance advices.