organizational structure

We are building our new intranet on Drupal. We are a group of companies, i.e. our organizational structure consists of sub-companies, which again have sub-companies or departments, which also can have sub-departments and/or employees belonging to them. We need to have this organizational structure in our Drupal-based intranet system, both:
1) in terms of content: displaying the corporate structure as a hierarchical list of companies, sub-companies, departments; displaying employee listings per company and department;