To enable users to see Inter-Company billing job codes and allocate charges, or if the user is only authorized to see some of the companies, we need to proceed as follows: 

1. Go to Settings
2. Go to Setup submenu
3. Click application settings tab
4. Choose Inter-Company from the list
5. Set Enable security by company to True or False
6. Click save

By setting to true, users will only be able to see the Inter-Company vendors assigned to their profile under Security > Manage Users > companies.