In Access Governance, a Local Group is a way of making a filter's ruleset evaluate multiple expressions to return a single true or false result. There are two logical group operators: AND, as well as OR. A plain English example of a logical group would be "I want to see all employees whose job title is 'Chief Executive Officer' OR 'Chief Financial Officer'". Let's see how that example works in Access Governance.
After choosing which object you want to filter on (in this case, the Profession object), right click on that object and select Add Logical Group from the context menu. This will add a dropdown field where you can select either the AND or the OR operator. Once you've chosen the operator you want, right click on the logical group itself and add your first expression. After filling out that expression, right click on the logical group again to another, and as many more as you need.
When you are finished, you will have a filter ruleset that might look like the following screenshot. Notice that the expressions come after the logical group.