Use Roles and Role Membership in Current RMS to control what users can see and do in your system. When create a role, toggle “Can access everyone’s opportunities?” to NO to stop users with this role from accessing opportunities that they’re not the owner of or a participant of. 

This impacts all places where you can access opportunities, like projects and global check-in. The user will only see opportunities that they can work on.

On most screens, this hides the opportunities altogether. For example, on a project or product page, users will only see the jobs that they can access. There’s a handy note of the number of opportunities that they can’t access.

Keep in mind that this only affects opportunities, not invoices. Remember you can use roles to restrict access to invoices to prevent users from seeing, creating, editing, or deleting them. See: Restrict access to parts of the system using roles