How to generate a separate invoice by month for past billing periods

Summary: Our business requirement is to generate a separate invoice (by month) for the past billing periods, because our customers could have a different PO for each month/quarter and they would want to make payment by PO. Also, as per our business policy, we can't create invoices with invoice-date/gl-date in the past, and we can't post the transactions to the past accounting periods (as it would be closed).

Current functionality, does not support this and it generates a single invoice for all months in the past billing periods.

How do we achieve this with standard functionality?

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