PDF attachments

Hello

I found a bit of code a while back that would check if any PDF’s were uploaded to the post as attachments and if so display them in my theme.

Here is the code:

http://pastebin.com/GqQUHP1J

Would anyone be able to help me modify this code to do the following:

I have 5 categories (a,b,c,d,e for explanation purposes) as a custom post type called product_categories.

I need to show all the PDF’s in category a (attachments would be uploaded on posts within this category) and seperately the same for category b, c and so on..

Any help would be greatly appreciated.

Regards,
Brendan