customize bigcommerce shipping options

We have a special way we set up our product shipping options, and unfortunately the standard bigcommerce configuration does not offer this. We need the shipping to be set up so that it charges What we need: Regular shipping (displayed to customers in the "regular" customer category) 48 States: $6.00 for orders under $10.00 $4.85 for orders $10.00 to 44.49 $45.00 or over FREE UPS ground shipping – other shipping options (such as second day, overnight, etc) are charged less cost for ground. If they want priority mail, it needs to add an additional fee of $2.75. Wholesale shipping (displayed to customers in the "wholesale" customer category: 48 states: 4.85 for shipping on orders less than $75 UPS ground free for orders over $75 Outside 48 states/international: actual cost Add feature: shipping will only be charged if product contains x number of product 1, or y number of product 2, AND costs at least $50.00. (If the order is more than x number of product 1 or more than y number of product 2 and costs more than $50.00, then they WOULD be charged.)