function bbg_remove_doubles( $has_activities ) {
    global $activities_template;

    foreach( $activities_template->activities as $activity_key => $activity ) {
        //var_dump( $activity->type );
        if ( 'new_blog_post' == $activity->type ) {
            // Get the parent item
            $parent_id = $activity->item_id;

            if ( empty( $activities_template->activity_parents[$parent_id] ) ) {
                return $has_activities;
            } else {
                $parent = $activities_template->activity_parents[$parent_id];
            }

            // Is the activity author the same as the parent author? If so, remove
            if ( $parent->blog_id !== 1 ) {
                unset( $activities_template->activities[$activity_key] );

                $activities_template->activity_count--;
                $activities_template->total_activity_count--;
            }
        }
    }

    // Reset indexes
    $activities_template->activities = array_values( $activities_template->activities );

    return $has_activities;
}
add_filter( 'bp_has_activities', 'bbg_remove_doubles' );

function bbg_dont_remove_doubles_on_ajax() {
    remove_filter( 'bp_has_activities', 'bbg_remove_doubles' );
}
add_action( 'wp_ajax_new_blog_post', 'bbg_dont_remove_doubles', 1 );