How to restrict access to vendors across multiple ledgers

We have a large Oracle e-business suite instance consisting of multiple ledgers. Each ledger has one or more operating units. Each of these ledgers are a "division" that are separate from from one another. Our business users have expressed a requirement to segregate their vendors, i.e. they do not want to see vendors that do not belong to them and they do not want their vendors to be seen by other divisions. Each division has their own responsibility that has their MO Operating Unit profile option set. It is quite difficult to segregate vendors as there is no org id