How can we automate multiple credit memos to one invoice and one credit memo to multiple invoices?

We’re trying to build a logic where credit memos will be applied to invoices automatically. We have built a logic where one credit memo can be applied to one invoice. But we have other cases like one credit memo applied to multiple invoices and multiple credit memos applied to one invoice. We’re facing challenges to build logic for these to cases. Business also mentioned about the any excel logic by extracting open credit memos and open invoices and bases on input for mapping from business if it is achievable. If you have any workaround, please let us know. Thanks in