When editing or creating contact groups, you will see a view under the "Communication path" tab that contains a slider “Restrict communication channels”, a list of all other contact groups in your organization and a text that says:
“You can limit the communication paths between contact groups. Only connected contact groups are allowed to communicate. If no other contact group is selected, users of this contact group can only communicate within their own group.”
When the slider is activated, restrictions apply to the ways members of the contact group you are editing are able to communicate with other users.
This means that contact group members can only see the other contact group members in their contacts and can only create a conversation with them.
All members of a channel can still be listed, but no conversation can be created with users for whom communication channels are restricted.
In addition, all contact groups are listed below. Selecting a contact group here enables communication with contact group members of the selected contact group.
If a user is a member of multiple contact groups, they can communicate with all users to whom one of their contact groups grants them access.
So, for example, if you are a member of an unrestricted contact group (slider deactivated), you can always communicate with all users, regardless of which other restricted contact groups you are also a member of.
Communication channel settings for chat bot
In order for users with restricted communication to continue to create video conferences, they must be allowed to communicate with the "Chat Bot" user. To do this, read the article Enable the Chat Bot for users with limited communication.