How to separate activity stream posts

[sv1cec]

Is there a way to add a line under each entry in the Activity Stream, to separate it from the one below? So far, the only thing I've managed to do, is to add a border around each entry, but it looks kind of silly in that way.

You may have a look here:

http://forum.m1911.org/activity.php

I would prefer if I could add a simple <hr> there, but that means changing all the activity templates.