How can we add group in Visibility settings of Posts for Homepage?

Problem/Motivation

I want to restrict regular users to post anything on the site.
Instead if they want to post something they can select Group in visibility setting(How to add group in homepage post block visibility setting).

Steps to reproduce

Login as regular user, on homepage you will see post block on the top in which default visibility is community. Here i want group option in visibility setting, so that regular user cannot post anything which will be visible to community.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes