sitemap

How can I add another tree(not sure if that the correct term) to "Account dpt"?
sample
Home
      department
            Account dpt
                  billing
                  adjustment
                  close out date
              Representative
                  etc
            Sales
                  etc




<?xml version="1.0" encoding="utf-8" ?>
<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
  <siteMapNode url="/" title="Home"  description="Home">
    <siteMapNode title="Department"  description="">
      <siteMapNode url="" title="Account dpt"  description="">
          <siteMapNode url="~\test\test1.aspx" title="billing" description=""/>
          <siteMapNode url="~\test\test2.aspx" title="adjustment" description=""/>
        <siteMapNode url="~\test\test3.aspx" title="close Out date" description=""/>
      <siteMapNode url="" title="Representative dpt"  description="">
       
       
       

      </siteMapNode>