Making Flat Rate SMALL Box Available if only less than 2 pounds

I only want a Small Flat Rate Box option to show up if their order is less than 2 lbs. For both US and International.

How would I go about doing this?

I'm running the most 1.3.9h
I currently have USPS set up with:

Domestic Shipping Methods
PRIORITY, FIRST CLASS, PARCEL

International Shipping Methods
Priority Mail International, Priority Mail Int Flat Rate Small Box, Priority Mail Int Flat Rate Med Box

Thanks for any help

You could customize the code for the Priority to change which container is used based on weight ...

Currently, the setting is for all orders:

          //PRIORITY MAIL OPTIONS
          if ($key == 'PRIORITY'){
            $this->container = ''; // Blank, Flate Rate Envelope, or Flat Rate Box // Sm Flat Rate Box, Md Flat Rate Box and Lg Flat Rate Box

          }

But you could setup a case statement to base which choice is used for the $this->container based on the $this->pounds to set that ...

I know nothing of PHP, so how would that code look when finished?

It would require quite a bit of customization ...

First, to get the right container size in the section I showed you , and then to customize the output on the same conditions for what shipping options are actually displayed ...

If you are not good at coding, you mayneed to look to hirer a coder to write this for you ...

Yes, I have tried hiring someone at the freelance site recommended here. Unfortunately, the people that apply never meet the requirements I have set. I'll just see if I can figure it out on my own again.