This is something we’ve always struggled with due to vastly different timezones.
I suggest it’s user led, and our solution is focused on making it easy for users to create video calls, and invite the rest of their team.
This task probably involves the team calendar which is another UX task
We’ve always found Zoom a great platform for free videos calls (limited to 20mins), as it has excellent conference call functions
We also have all of these integrations built into our platform as potential tools to use to find a solution: https://meta.discourse.org/t/chatroom-integration-plugin-discourse-chat-integration/66522