This article is part of the Security & Permissions Guide
When using Advanced Permissions and roles, some record types need to be shared among users assigned to the same role or with users assigned to different roles. Sharing rules allow you to cut across the barriers of your role hierarchy and share viewing permissions by record type.
So, you can have a sharing rule that allows two manager roles to view each other's leads as well as the leads of the people who report up to either of them. And you can have another sharing rule for the three people in a salesperson role so that they can view each other's opportunities and help them prevent the creation of duplicates.
You can only use roles and sharing rules when a record type is set to private under organization-wide sharing.
When you're ready to set them up, see Configuring sharing rules.