[xsl] Grouping elements using XSLT

[Chad Chelius <cchelius@xxxxxxxxxxxxxxx>]

I have an XML file that looks like this:

<author>
<Firstname>Jane</FirstName>
<LastName>Doe</Doe>
<Firstname>John</FirstName>
<LastName>Doe</Doe>
<Firstname>Howard</FirstName>
<LastName>Johnson</Doe>
</author>

The DTD that I am trying to validate to requires that each person be  
inside of their own <author> element like this:

<author>
<Firstname>Jane</FirstName>
<LastName>Doe</Doe>
</author>
<author>
<Firstname>John</FirstName>
<LastName>Doe</Doe>
</author>
<author>
<Firstname>Howard</FirstName>
<LastName>Johnson</Doe>
</author>

Is this possible using an XSLT and if so, how do you do this?