Shared Channels support

[Brakistad]

Is your feature request related to a problem? Please describe.
We would like to make a channel dedicated for discussions in a private team, but be able share this discussion channel with other teams, to get more engagement in discussions.

Describe the solution you'd like
Support for shared channels,

Describe alternatives you've considered
Our alternative is to create a team that includes every member of every team we have, and have the discussions channel there.

Additional context
reference:

• Supported apps in shared channels
• Setup support for shared channels