@Neil: You can do most of what you need with Communications module.

You can do “live” communications. (But we moved it out of the Project in last version. All communication channels are now accessible directly from “Communications” link in activeCollab bottom bar)

If you wanted to refer the communication channel in a project, you can use it’s link URL anywhere in activeCollab. Post it in a discussion / task / comment / project description… So that people can quickly reach the project’s channel.

You can select all people or a set of people from a project (or otherwise) while creating a channel.

Communication channels are “confidential” – meaning only those people who are explicitly assigned to a communication can see it. This is better than Private in most cases.

HTH.