Keeping user roles in different realm than users

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Is it possible to authenticate a user against one realm (i.e.: LDAP) but 
authorize (obtain roles the user belongs to) against another realm (i.e. 
database)?
Any other solutions than writing an error-prone homegrown one that will allow 
to keep users in one realm, user roles in the other realm and still be able to 
use container-managed authentication with authorization. Best regards.Kamil