You can often determine the organizational structure of a company by using Hoovers or Mint Global and looking for those in charge of particular departments and those under them. This information is often the listings for Key Executives.

Reference USA
Reference USA contains information on over ten million U.S. companies. In addition to address and phone number, each entry includes officer names and titles, corporate affiliation, business type and size of yellow page advertising.

Orbis
ORBIS has information on over 55 million companies, including public and private companies, banks, and insurance companies. The information includes national and international companies.