Easy, open the Bullit featured php template,
find this line:
<?php query_posts('showposts=1&offset=0'); ?>
here you have to add the cats by ID like so:
<?php query_posts('cat=5&showposts=1&offset=0'); ?>
where cat=5 indicates your cat ID,
shown on this page in WP admin:
manage → categories → status bar
the number shows up by hovering your cat like so:
http://yoursite.com/wp-admin/categories.php?action=edit&cat_ID=5
you have to repeat this step on the next sections as well, like so:
change from
<?php query_posts('showposts=1&offset=1'); ?>
to
<?php query_posts('cat=ID&showposts=1&offset=0'); ?>
Note that the offset changed to zero, so it will show the latest post
from your desired category, this way you can show six posts from six categories
or leave the offset and choose only one category.
You can see the possibilites are endless.