How to make a Feature available only to certain Spaces? For a Drupal 6 Open Atrium site (i.e., Features, Spaces, Organic Groups) I'm running, I've created some custom Features that only really apply to a handful of the hundreds of groups on the site.

As it stands, the "Customize Features" config screen shows all the Features, including those I'd like to intentionally restrict to just a couple of special groups. 

What's the best way to prevent these special Features from being offered to every group, while retaining those Features on the special groups?
The features for each space are configured via the spaces_features_form() function. You could implement hook_form_alter() to selectively and conditionally remove features from specific groups.

function MYMODULE_form_alter(&amp;$form, $form_state, $form_id) {
  if ($form_id == 'spaces_features_form') {
    $space = spaces_get_space();
    // Populate the array with hard-coded NIDs, or whatever logic
    // needed to determine if these features should be allowed.
    if ($space-&gt;type == 'og' &amp;&amp; !in_array($space-&gt;group-&gt;nid, array(...))) {
      // Hide features foo and bar.
      foreach (array('feature_foo', 'feature_bar') as $feature) {
        $form['spaces_features'][$feature]['#access'] = FALSE;
      }
    }
  }
}