Existing Solution: Dealers and Vendors (external users) using Salesforce Licenses. They are assigned to Roles (Dealers at the bottom below Vendors). They own Accounts, Opportunities and other custom Object Records.
Proposed Solution: To make external Users (Dealers & Vendors) as Partner Users via Communities.
Observation: As per the documentation the provisioning is little tricky.
It requires creation of a Partner Account (this Account Owner's Role becomes important as it becomes logically above the Role Salesforce creates automatically while promoting a Contact into a Partner User). Partner Users to be created as Contacts under the Partner Account. Contacts under the Partner Account to be promoted as Partner Users. Salesforce automatically creates a new Role and assigns the same to the newly promoted Partner User.
Problem: How do we provision Partner Users from existing Salesforce Users. How do they fit-in into the existing Role hierarchy. Currently these Users own Accounts, Opportunities, Contacts and other Custom Object Records. Vendors are above Dealers in the Role hierarchy. How do we maintain the same hierarchy once transitioning the Salesforce Users into Partner Users. How does the Record ownership affect. While promoting Contacts into Partner Users a New User and a New Role is created.
Suggestions and advise from the community will be much appreciated.