[keycloak-user] Dynamically assign roles to user for single session

I have implemented different authenticators which users can choose when they login. Now, I would like to assign various roles to the user based on authentication method user has chosen. Those roles would be assigned to the user only in current session. Is this possible to achieve? I used a mapper to put user's decision on authentication method in the tokens, but how to map this property (field) to the specific role/roles? Best regards, Nikola