To be clear, I'm referring to on a different domain, not in our account. I can find no way to do that. I.e., in our SFB, we can easily talk to people in other companies so long as the federated settings are configured right. I want to go from my Teams to another company using SFB.
Well in my experience, whenever people ask for Teams and SfB interop, it's almost always about federation, so I guess I assumed this was the case here too. We have enough methods to communicate internally even without Teams in the picture, but the ease of use SfB federation offers for exchanges with external parties is definitely a huge argument against switching to Teams, for many orgs. Anyway, that saga will be over soon.