Answer :
- Microsoft Entra ID P1 for all the internal users and external guests that use Teams
Explanation :
The Microsoft 365 groups naming functionality requires Microsoft Entra ID P1. As the functionality cannot be scoped, to only include some Teams, it must, therefore, be licensed for all staff members and guests in the tenant that use Teams. This does not fall into the 1:5 guest ratio.Using a Microsoft Entra naming policy for Microsoft 365 groups requires that you possess but not necessarily assign a Microsoft Entra ID P1 license for each unique user (including guests) that is a member of one or more Microsoft 365 groups.