ok, I think I know what you are trying to do and here is a possibe solution. Lets take this case, you have a couple pages and one is 'Directions' with child pages of North, South, East and West. You also have a page MEals with child pages of breakfast, lunch, and dinner, and you are using the pages widget. This is what the HTML might look like
HTML Code:
<!-- Left Sidebar -->
<td id="left">
<div id="pages-2" class="widget widget_pages">
<div class="widget-title"><h3>Pages</h3></div>
<ul>
<li class="page_item page-item-50"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=50" title="archive’ss">archive’ss</a></li>
<li class="page_item page-item-1189"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=1189" title="Calendar">Calendar</a></li>
<li class="page_item page-item-3"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=3" title="Directions">Directions</a>
<ul>
<li class="page_item page-item-7"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=7" title="East">East</a></li>
<li class="page_item page-item-42"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=42" title="North">North</a></li>
<li class="page_item page-item-1192"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=1192" title="South">South</a></li>
<li class="page_item page-item-5 current_page_parent"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=5" title="West">West</a></li>
</ul>
</li>
<li class="page_item page-item-2"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=2" title="Meals">Meals</a>
<ul>
<li class="page_item page-item-95"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=95" title="Breakfast">Breakfast</a></li>
<li class="page_item page-item-44"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=44" title="Dinner">Dinner</a></li>
<li class="page_item page-item-40"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=40" title="Lunch">Lunch</a></li>
</ul>
</li>
<li class="page_item page-item-648"><a href="http://192.168.48.99/~paul/zenofmud/?page_id=648" title="splash">splash</a></li>
</ul>
</div>
</td>
<!-- / Left Sidebar -->
but that will show everthing and you only want to show the child pages when you are on them. Here is the CSS inserts that will make it all work
HTML Code:
.widget_pages li.page-item-2 ul {display:none;}
.widget_pages li.page-item-3 ul {display:none;}
.widget_pages li.page-item-2.current_page_item ul, .widget_pages li.page-item-2.current_page_ancestor ul {display: block !important;}
.widget_pages li.page-item-2.current_page_item, .widget_pages li.page-item-2.current_page_ancestor {background: green;}
.widget_pages li.page-item-3.current_page_item ul, .widget_pages li.page-item-3.current_page_ancestor ul {display: block !important;}
.widget_pages li.page-item-3.current_page_item, .widget_pages li.page-item-3.current_page_ancestor {background: blue;}
the first two lines hide the children menus,
the next two lines will display the children of page 2 (Meals) and color the block green when you click meals or any of it's children.
The last two lines will display the children of Directions and color them blue when any of them are selected.
Hopefully this is what your looking for.