Hi,
I think Portfolio authorization is not included in the trader authorization 'coz it it only involves authorization limit on product types, transaction types, product categories & contract type. You can limit the authorization of your traders by creating individual roles for the portfolio (by location) in tcode PFCG. The roles are usually done by basis team but it's the functional consultant who identifies the roles and users to be assigned including the details of the authorization objects.
Regards,
Chaikaru