This Condition located on the Enrollment category tab in Search Builder will look for individuals who are in a Sub-Group with a specific name.
If you have multiple organizations that use sub-groups named Leaders, you can enter Leaders as the Value and find everyone who is in a sub-group with that name within the Program and/or Division specified.
Sometimes that is easier than trying to select individual Member Types to find the leaders.
You can also enter a sub-group prefix and find those in groups beginning with that prefix. Prefixes are used in large organizations that have a lot of sub-groups. You can categorize groups that are similar in nature by assigning them a prefix.