What are the best controls to use when de-centralizing Supplier data entry?

Our Supplier data entry is currently centralized. One of our Purchasing departments wants access to enter Purchasing related supplier data. They already use the "New Supplier Request" pages to submit new supplier information but they want to be able to make changes to existing data, too. We are on 12.1.3, multi-org, and multi-ledger, are using SLM, Sourcing, and iSupplier. Knowing how global supplier data is, we need ideas to restrict or monitor the supplier and supplier site data that affects payments, including elements of the Purchasing sites. Does anyone have first hand experience with this using workflows, alerts, personalizations, etc?