[SOLVED] Remove multiple comment footers per category

Hi,
I had a question about a thread that is closed, the thread in question is:

http://forum.bytesforall.com/showthread.php?t=4623

There is a line there that works, but I want it to work on multiple categories:

<?php if (!in_category('5')) { bfa_post_footer('<div class="post-footer">','</div>'); } ?>

I was wondering if you can add more than one category to this? I tried making it: ('5', '6') but that doesn't work. I'm not sure if you CAN add more than one category?

Thanks in advance!