What permissions changes do I need in order to generate a token for a Google Group?

Question

I'm trying to make a request to get messages from a Google Group, but the token request that works for getting messages from a User does not work for a Group, indicating that there is some change I need to make to the Group itself potentially. What needs to be done in order to do that? I see that it's possible but what needs to be done in order to get a credential for this request?