In Policy Exception Approval group field OOB showing two group where this is configured?

In Policy Exception there is Approval Group field. OOB when we click on magnifying glass of Approval Group field it shows only 2 groups to select 1. Compliance Managers 2.IT Risk Managers. If I want to add other groups how can I add there?
There is no reference qualifier applied on the approval group field where can find the configuration?