Hide some portion on single.php base on author

if( !in_array('Aggregator', get_the_author_meta('roles')) ){
    //If user is not aggrigator display the info
}

That will get the authors roles as an array for the current post. You can pass a post id along with the ‘roles’ to get the data from another post.

Also note that your Aggrigator role is possibly set-up in word press in lower-case so make the if statement reflect this.