Show Excerpt in Search except where condition is true

The script below is from a slightly customized search.php. I’d like to modify it so that the excerpt doesn’t show if it is a defined term.
e.g. in all circumstances I want the excerpt to show unless the excerpt is exactly ‘abcdef’.

Any help greatly appreciated.

<?php
/**
 * The template for displaying Search Results pages.
 *
 * @package WordPress
 * @subpackage Twenty_Ten
 * @since Twenty Ten 1.0
 */
 get_header(); ?>
		<div id="container">
			<div id="content" role="main">
<?php if (have_posts()) : ?>
		<h2 class="pagetitle">Search Results</h2>
		<?php while (have_posts()) : the_post(); ?>
			<div id="ge-search" <?php post_class() ?>>
				<h3 id="post-<?php the_ID(); ?>"><a href="<?php the_permalink() ?>" rel="bookmark" title="Go to <?php the_title_attribute(); ?>">
				<?php the_title(); ?></a></h3>
<? the_excerpt(); ?>
			</div>
		<?php endwhile; ?>
	<?php else : ?>
		<h2 class="center">No posts found. Try a different search?</h2>
		<?php get_search_form(); ?>
	<?php endif; ?>
<h2 class="center">Another search?</h2>
		<?php get_search_form(); ?>
			</div><!-- #content -->
		</div><!-- #container -->
<?php get_sidebar(); ?>
<?php get_footer(); ?>