A communication/collaboration system enables a first user at a first entity to define a collaboration object, and to invite a second entity to collaborate on the collaboration object in accordance with a hierarchy with corresponding permissions. A second user at a second entity is enabled to collaborate on the collaboration object. A communications log regarding the collaboration between the first user and the second user is maintained. A communications log between the first user and other users at the first entity is maintained. A communication interface is displayed on the first user computer system that displays the log of communications between the first user and the second user on the collaboration object, together with the log of communications regarding the collaboration object between the first user and other users at the first entity, and excluding communications regarding the collaboration object between the second user and other users at the second entity.