Private Posts visible to user list

For the following idea, could you please let me know if you know of an existing plugin or have any ideas that would allow me to accomplish this.

Let’s assume I have a new install of WordPress with BuddyPress. I would like to let any user make a WordPress post that is private to most, but visible only to a specific set of users per post. The list of users they could select would be from other users they are confirmed friends with. I understand this can be done with based on groups. I’m hoping to avoid users needing to create a group before they can define who can see the post.

Also, authorized users who can view the post will be able to comment.

Thank you,
Ryan