Are you able to space a navigation list to have vertical spaces between certain `<li>` tags using CSS and not JavaScript & JQuery?

Example: <http://jsfiddle.net/ssqnY/>

It needs to be responsive with the height of the containing div or window height.
The structure of the navigation list is below:

```
<ul>
    <li><a href="#">Link</a></li>
    <li class="spacer"></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li class="spacer"></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
</ul>

```