How can I programatically load a group?
Adding my comment as an answer:

$groups = \Drupal\group\Entity\Group::loadMultiple($ids); is all that is needed to load the groups based on IDs. Group::loadMultiple() does the storage bits already, so no need to duplicate the work.

So the full snippet would be something like:

&lt;?php

$groups = \Drupal\group\Entity\Group::loadMultiple($ids);
if ($groups) {
  $content = \Drupal::entityTypeManager()
      -&gt;getViewBuilder('group')
      -&gt;viewMultiple($group, 'teaser');
}