Shipping Discount Voucher vs. Price Rules

[Whispar1]

I am trying to figure out the best way to set up $4.99 flat rate shipping for a specific product line in my store. I have created a carrier called "4.99 Ground Shipping" so that I can select this as a carrier option when creating the product. However, I do not want this to be available unless the order is over $99. If the order does not reach $99, I need regular ground shipping to be available as well as expedited shipping options (which will all carry the standard shipping costs)

 

I would rather not create a voucher where the customer must enter it at checkout. It would be nice if their order is over $99, it is available. If not, then standard shipping options will be available. Is this beyond the scope of the standard Prestashop Shipping Modules?