Use Xpath to filter the request based on the departments in manger’s dashboard
like [department = $manager/account.department ]
Make sure to replace $manager with the appropriate XPath expression or variable representing the manager's data.
You need to make a department entity and make a references to employers of that department and make another reference to the manager(s) of that department. This way when a department is selected you can then retrieve the department of this employer and from the department retrieve the manager(s) of that department.