The most optimal and scalable solution is to use the Partner Role Hierarchy. When a partner account (the dealership) is enabled for community access, Salesforce automatically creates a dedicated, three-level role hierarchy for that account: Partner User, Partner Manager, and Partner Executive. By assigning the service agents to the Partner User role and their dealer manager to the Partner Manager role within the same dealership account, the standard role hierarchy sharing mechanism grants the manager visibility into all records, including cases, owned by their subordinate service agents. This approach requires no custom sharing rules and scales automatically as new dealerships are added.
Why Incorrect Options are Wrong
B. Create a sharing rule to share cases created by service agents with their dealer manager.
This is not optimal because it would require creating and maintaining a separate sharing rule and corresponding public groups for each of the thousands of dealerships, leading to significant administrative overhead and potential performance issues.
C. Create a sharing group to share cases created by service agents with their dealer manager.
Share Groups are used to share records owned by internal Salesforce users with external community users, or records owned by high-volume community users. They do not facilitate sharing between standard partner community users based on a managerial relationship.
References
1. Salesforce Help, "Partner Role Hierarchy": "When you enable the first external user on a partner account, a user role hierarchy is created for that account... The partner roles are created in a three-level hierarchy: Partner User, Partner Manager, and Partner Executive... Having a role hierarchy for your partners means that... partner managers can see all the data of partner users." This directly confirms that the role hierarchy provides the required visibility.
2. Salesforce Architects, "Record-Level Security": The guide explains that the first line of defense for vertical data access is the Role Hierarchy. It states, "The role hierarchy enables users above another user in the hierarchy to have all the privileges of the user below them... This is the standard behavior and cannot be changed." This principle applies to both internal and partner role hierarchies.
3. Salesforce Help, "Share Records Using Share Groups": "A share group allows you to share records owned by Salesforce users in a share group with external site users." This documentation clarifies that Share Groups are for sharing from internal to external users, not between external users in a hierarchy, making option C incorrect.