Add groupby to query_posts

Hello,

what I’m trying to do is grouping posts by its ID. I don’t know why, but I get duplicates.

So what I tried was to do the following:

<?php
  $args = array(
    'post_status' => 'publish',
    'author' => 6,
    'groupby' => 'wp_posts.ID',
    'paged' => (get_query_var('paged')) ? get_query_var('paged') : 1,
  );
  query_posts($args);
  get_template_part('template', 'loop'); ?>

But that doesn’t do anything. Anyone knows a solution?

Thanks