Flat shipping rate for unlimited products from one category

Site URL: http://joyfulblooms.com.au

Hi all,

I predominately sell singular items on my website, but I am creating a ‘build your own gift box’ category on my website.

The way I have set it up is that the customer selects all of the items they want to include in their gift box.

Currently the shipping on my website is set up by weight, so as each gift box item goes into the cart it is increasing the shipping amount... However I am wondering if there is a way that I can create one shipping amount for anything from that category, no matter how many items the customer selects. For example, they select 3 items from that category and shipping cost is $20, or they select 8 items from that category and the shipping cost is still $20.

I am pretty new to all of this so have come this far without any issues... I am hoping someone might have a suggestion on how to set this up, or even if there is a better way to build this part of my website.

Any help would be appreciated.

Thank you