BigCommerce help needed

Looking to hire someone who can assist us with an issue we are having with BigCommerce. We have products we sell & there are a good number of manufactuers/brands who do not allow discounting on their products. However, BigCommerce does not have a way to restrict brands when creating coupon codes. The only function allows for creating a category & dumping these brands in this category...however, when creating the coupon it states "This coupon code can be used with these categories:" >> so if you select everything but the special category that's been created to avoid the discounting...it means that you cannot have these products listed in any other categories, which is not helpful to store function. We have 1000's of products and need a functional workaround or script or app that will take care of this issue for us.