Allocating Partial payments to multiple invoices

Hello:

I have a scenario where I have large number of records and each record has its own record balance (imagine an invoice). Each record is unique, there are no duplicate records or multiple invoices. One record= one balance or invoice.


I received a large lump sum payment which closed out the outstanding balance, however, I didn't bother to allocate the funds to each invoice. I can't use a bank statement to allocate the amounts because the amounts were not transferred into the operating account in amounts equal to even multiple invoices.

Can someone give me some insight how to apply these payments to the records.

thanks for any assistance.