If you've tried activitystream_identicagroup module for Drupal, but still don't love the display, here's what I did for Frog and Owl:

I installed and enabled activitystream_identicagroup module, then edited one user's settings to add frogandowl group to their activitystream. Note please that the identica field (if enabled) and identica group field are totally different things -- identica group is toward the bottom of the form. Then, I created a view for what I thought was a nicer-looking identicagroup block.