wp-admin list only parent posts

When admin creates a post with five custom fields I creates 5 posts with post_parent id to main post. But these 5 posts are also showing in posts listing table which I want to hide.

In /wp-admin/edit.php where wordpress shows all posts (parent & child) under All/Publish I want to show only Parent posts having post_type = post because I am using other post types as well but only want to change view where post_type = post.

I knows for this I must need to edit core file, no matter I can. After searching in wp-admin/includes/class-wp-list-table.php I found

    /**
     * Generate the <tbody> part of the table
     *
     * @since 3.1.0
     * @access protected
     */
    function display_rows_or_placeholder() {
        if ( $this->has_items() ) {
            $this->display_rows();
        } else {
            list( $columns, $hidden ) = $this->get_column_info();
            echo '<tr class="no-items"><td class="colspanchange" colspan="' . $this->get_column_count() . '">';
            $this->no_items();
            echo '</td></tr>';
        }
    }

which creates rows for posts list table but I can not found where to set condition & custom query :

IF (post_type == 'post'){
    // list only parent posts
}else{
    // do default behavior
}

I searched almost 3hrs but no solution found. Okay if it is not possible then can we show same Hierarchy for posts like for Pages parent/child relation.