Previous: Deleting a Group
By default, Groups are shared within the entire organization. If your organization would like to keep groups private within a team or individuals, follow these steps to change the sharing rules.
Note: You need administrator privileges to perform the following actions
Go to Setup > Security Controls > Sharing Settings
Click Edit at the top of the page.
Change the drop-down next to Group to Private and then click Save.
That’s it, now your groups are private and can only be seen by the person creating them or someone above them in the Role hierarchy.