This Plugin allows you to select specific users by user name, or by role name who can view a specific post content or page content.
Basically it adds a meta box to the post or page edit screen and lets the user select specific users by name or roles and then when you call that page content using “the_content();” function it check using “the_content” filter if the current user is one of the users you have selected or if his role match’s the roles you have selected and shows the content, otherwise it displays a message