If 5 posts then… If 4- posts then… ??

I post quite frequently so my monthly archives can get pretty long and I’ve decided on this format:

————————-
Archive for May 2006

All posts in this month: (Loop 1)

<ul>
<li><a href="#postId" title="Preview this post">Post Title</a></li>
<li><a href="#postId" title="Preview this post">Post Title</a></li>
<ul>
Post previews: (Loop 2)
Title
Excerpt … More link
Post Meta Data
Title
Excerpt … More link
Post Meta Data
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I’m ok with all of that, the only problem is when the monthly/category archives still only have a few posts. For example there’s a list listing one post and then a preview of one post. Is there a way for me to tell WordPress:
<?php if (5+ posts()) { ?>
<em><--Do this--></em>
<?php } else { /*Less than 5*/ ?>
<em><--Do this--></em>
<?php } ?>

??

thank you!