Is there a way to process non-PO invoices without enabling Procurement Function at BU?

Summary:

There is a requirement that: We have a BU in which there will be no Procurement function require. But the non-PO Invoices and Intercompany invoices need to be processed. So for this we require Supplier and Supplier Site. Now to create these Sites we need to have Procurement BU and for that we need to enable Procurement Function at BU level and do the set-up of task "Configure Procurement Business Function".

So, above mentioned is one way to do it. We wanted to check if there is any other workaround/ or other way to process Invoices without Enabling Procurement Function?