Universal Containers is implementing a Partner Community.

The sharing setting that would allow users to collaborate with their peers who work for the same partner firm, but not with any users outside of their firm, is Portal User Visibility. Portal User Visibility is a setting that allows portal users (such as Customer Community or Partner Community users) to see other portal users who have the same role or a role below them in the portal role hierarchy. This setting enables portal users to share information and collaborate with their peers within their own firm, but not with other firms.