Admins have the ability to turn off Public Comments and Private Replies for all Posts of any Group. This will ensure that Members and Managers are not able to reply to any Posts in the Group. 

DISABLE COMMENTS IN A GROUP

Follow the steps below to disable Comments in a Group.

• Navigate to the desired Group.
• Click the three dot icon.
• Select Settings.

• Select Member Permissions.
• Toggle off Public Comments and Private Replies to the left.

• Click the Save changes button. 

This permission setting can be used in conjunction with turning off other Post types to create a Group that serves as Community announcements, allowing Admins to can share important Community updates. 

To learn more about general member posting permissions, check out this help article.