Putting this item under review so we can investigate the scenario. Currently you can use Flow to automate posting. DRI/POC can be maintained in a list or file and message can be sent to Teams channels at designated intervals. For schedules as mentioned you might also consider using the Shifts app inside of Teams. This would provide additional features like shift swapping, activity lists for each shift etc.
An error occurred while saving the commentJoshua Drake commented
I want to also be able to do this to Chats.
Unfortunately because of changing priorities, this feature was moved to the backlog. The team hopes to pick it up again in the near future.