Knowledge Management Externally Published documents

I have a  requirement to publish knowledge documents externally so that only the department publishing the knowledge doc should be able to access it through ESS. 


eg Department 'A' publishes Externally and only members of this department can access it through ESS, similarly Department 'B 'publishes Externally and only members of department 'B' can access it.

HPSM version 9.31 using solr search engine