How to use People Group when creating conditions for a Filtered List

We are trying to utilize Filtered Lists for assigning a Journey to a specific subset of our employee population. In doing so, one of the conditions that we need to configure is for certain combinations of Legal Employer and People Group. For example:

IF ((Legal Employer = Employer1 OR Legal Employer = Employer2 OR Legal Employer = Employer3) AND People Group = P) THEN
EXCLUDE

Within the list of available attributes for Filtered Lists conditions, Legal Employer is directly available; however, People Group is not directly available. Here is the current list of attributes:

• Location Code
• Location Name
• Department
• Department Title
• Job Code
• Job Name