API Bigcommerce Fedex hack

I moved my store to Bigcommerce. I previously running a zencart. Zencart would split weight into X number of boxes if over Y amount of weight. I.E. if the total combined weight of and order was $180 lbs it would split it into 3 even amounts of weight 3 x 60lbs boxes. Then the Fedex API would get a quote for 1 - 60lb box to the buyers destination and then the API would multiply the quote by 3 to get the proper amount of shipping to charge. This is not an option in Bigcommerce and I was hoping we could replicate the same hack. Right now there is NO possible solution in Bigcommerce for us to give quotes on our multiple heavy product orders. Thanks!