Why don’t you simply create a new sidebar… It will be clearer for you and will lighten your sidebar.php.
Create a file in your theme folder : sidebar-thenameyouwant.php
put your sidebar code there like this ex :
<div id="secondary">
<?php dynamic_sidebar( 'sidebar-xyz' ); ?>
</div><!-- #secondary .widget-area -->
in your themes function.php… add :
register_sidebar( array(
'name' => 'Custom posts sb',
'id' => 'sidebar-xyz',
'description' => 'blablabla',
'before_widget' => '<aside id="%1$s" class="widget %2$s">',
'after_widget' => "</aside>",
'before_title' => '<h3 class="widget-title">',
'after_title' => '</h3>',
) );
then in your custom taxonomy page you call the right sidebar
<?php get_sidebar('thenameyouwant'); ?>
it will automatically load the code from your sidebar-thenameyouwant.php
Of course, the new sidebar will be in your admin Appearance > Widgets… You can slide widgets into it or just edit the new sidebar file directly. If you want to load widgets you have to have the dynamic_sidebar php call like above…
hope this helps.