SAML Attribute format for Gateway firewall policies

I’m trying to build some DNS policies for the Zero Trust Gateway firewall policies.

I want the policy to have some basic traffic expressions (that’s ok), and the policy to be applied to users members of a certain group in Azure AD (now Entra ID). As an example, let’s assume the policy needs to be applied for users members of the mygroup group. For it I’d like to use SAML attributes

I did a quick search in the community forum and saw a post [1] referencing the following SAML attribute name: http://schemas.xmlsoap.org/claims/Group

However, when I try to plug that value in the “Attribute name” field, I get an error: “Invalid SAML attribute”. I’ve also tried with http://schemas.microsoft.com/ws/2008/06/identity/claims/groups with the same outcome.

What is the expected format for such value? I cannot find any clear references in the documentation. Must admit I’m not too familiar with SAML so please forgive me if I assumed some basic SAML stuff (never late to learn a bit more).

[1] ADFS/SAML Groups in App policies