Hi,
I wanted to share with you that I have figured out how to do this.
First of all, create separate categories for each group of blogs beginning with each letter of the alphabet for which you have blogs; for example: blogs_a, blogs_d, etc, and make note of the category id WordPress assigns to each one.
Edit your sidebar.php file where you want the blogroll to appear and insert this code:
<h2>Great Blogs (or whatever you want to call them)</h2>
<?php wp_list_bookmarks('category=7&categorize=0&title_li=0'); ?>
replace the "7" in the string "category=7" with each new blog category you want to present and insert the
codes to separate each group.
That's it!