Use Private Channels

Restrict visibility and posting to approved members.

Creating a private channel

1. Create a channel, name it, optionally add an emoji/icon.
2. Set visibility to private.
3. Add approved members.

Non-members don't see it listed at all — invisible, not just locked.

Managing access

The group owner and channel creator are automatic channel managers. The group owner can't leave a private channel once created. Convert public ↔ private later (switching to private doesn't retroactively hide history from prior members).