jQuery nested ul navigation menu, accordion or tree menu?
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I am unsure of the best option to implement a side navigation menu, that has a maximum of 4 nested UL's. The biggest problem I am having is that some headings that need to expand to show child elements also link to individual pages. 

I think the best method is to not link to that individual page by default, instead have an icon next to it which links to that page. The issue I have here is accordions don't seem to like this when Navigating and selecting active items. 

I've done some research on jQuery Tree navigation menu's but I am unsure of:  
1) how customisable they are,  
2) I can have a heading show children and go to an individual page somehow.

What is the best option here for me, please?  Oh and the solution needs to be HTML / CSS / jQuery based only, thank you.

HTML (cut down, there's about 100 links overall):

    <ul class="menu">
      <li class="menu_level_1"><a href="/" >Home</a></li>
      <li class="menu_level_1"><a href="/link2" >Link 2</a></li>
      <li class="menu_level_1">
         <a href="#" >Link 3</a>
         <ul class="sub_menu_2">
            <li class="menu_level_2"><a href="/link4" >Link 4</a></li>
            <li class="menu_level_2"><a href="/link5" >Link 5</a></li>
            <li class="menu_level_2">
              <a href="#" >Link 6</a>
              <a href="/link6" >Go to Link 6</a>
              <ul class="sub_menu_3">
                <li class="menu_level_3"><a href="/link7" >Link 7</a></li>
              </ul>
            </li>
         </ul>
      </li>
    </ul>