Want to chat with an external team member? Now you can - all you have to do is add them to your team! (External team members are people outside of your organization such as partners, clients, consultants, etc.).
So, let's say your marketing team is collaborating on a project with a freelance designer. Send her an invitation to join the team. Once she accepts, she can start a 1-to-1 chat with anyone on the team (and vice versa). And if she belongs to other teams in your organization, she can chat with those team members too.