You can try using the .current-menu-item li a"first-child selector. Here is an example I've used in the past to highlight the current menu item only:

#menu .current-menu-item {
background:white; 
}
#menu .current-menu-item li a:first-child { 
color:white!important;
}
#menu .current-menu-item a { 
color:black !important ;
}


You will need to change the #menu to your id or class.

Styling issue with custom menus and sub menus
I have a shapefile with overlapping polygons - network buffers around people's homes. I am trying to clip features such as tree canopy polygons and street polylines so that I can join the set of clipped features contained within each buffer to each network buffer polygon. Unfortunately I cannot get the Clip tool to clip the input feature polygons at the edge of the clip feature polygons if the latter overlaps with another clip feature polygon. How can I get the Clip tool to treat each of my clip features separately? Or is there another approach?  I'm working in ArcGIS 10.
