Hi Andrew,
Is it possible that your question refers to ]project-open[? Then please look at http://www.sourceforge.net/projects/project-open/ for help.
This OpenACS forum is about the _underlying_ Web framework that is used by ]project-open[. However, the community members here usually don't know much about the details of using ]po[.
To answer your questions: The Employee - Company relationship give the employee the permission to read the particular object (company, project or office).
A user (no matter whether employee or customer) can see the objects (companies, projects, offices) where he or she is a member.
For details please check in Google for "project-open permissions". You'll find several PPTs with more information.
Bests,
Frank
mailto:frank_dot_bergmann@project_dash_open.com
http://www.project-open.com/