Hello. I'll try to be as specific as possible as shortly as possible. :)

I am using the FedEx module by numinix located here: https://www.numinix.com/fedex-web-se...b3bf343cd189ce

What would be the easiest way to disable this shipping module and only allow it to be selected for certain categories? Specifically, the categories are 17-23. 18-23 are all subcategories of 17 like this:
[FONT="Courier New"]
17->18->20
------->21
--->19->22
------->23
[/FONT]

So basically I have two modules, USPS and FedEx. I want USPS to always show, and I want FedEx to only show as an option for the above categories. I'm also fine with creating a new column in the products table if necessary but I'm thinking that won't be needed.

As always, thanks for your help.