Insider risk management policies in Microsoft Purview target users based on priority user groups.
If you want to monitor a specific project team, you must first define those users in a priority user group so that policies affect only them.
This approach:
Minimizes the impact on users not part of the project.
Reduces administrative effort since you don't need to manage multiple security groups in Entra ID.
Reference:
Microsoft Learn: Priority user groups in insider risk management
Quote: "To focus risk management policies on specific users...create and manage priority user groups in the Microsoft Purview compliance portal."