well, i suppose it will all depend on which template you are using and what script is creating the url. most likely, i think you could modify:

includes/templates/YOUR_TEMPLATE/sideboxes/tpl_categories.php

from within that script you could add change the following line:

PHP Code:
$content .= '<a class="' $new_style '" href="' zen_href_link(FILENAME_DEFAULT.'&pg=store'$box_categories_array[$i]['path']) . '">'
to something like
PHP Code:
if ($box_categories_array[$i]['path'] == 'cPath=7') {
      
$content .= '<a class="' $new_style '"  href=\"www.somewhereawayfrombookoasis.com\">';
} else {
      
$content .= '<a class="' $new_style '" href="' zen_href_link(FILENAME_DEFAULT.'&pg=store'$box_categories_array[$i]['path']) . '">';

if that does not more work, i would look to see if your site has the following files:

includes/classes/categories_ul_generator.php
includes/classes/categories_ul_generator_template.php

if they are there, you might need to modify those files instead.

good luck!