Restricting access to OTBI Subject area and data elements within a subject area

Summary

How do we restrict subject area access to a user through security role?

Content

Subject area access is driven by duty roles. A duty role  'Workforce Transaction Analysis Duty'  for example is mapped to 10 subject areas. My first question is if it is possible to create a role that limits access to specific subject areas ? In the above example: we would like the user to have only access to 5 subject areas within the 10 that 'Workforce Transaction Analysis Duty' provides access to.  In other words, how can I give access to just the specific subject areas that the user needs?