GA attic space to be part of air conditioned space

Not yet constructed. The roof for the whole house is my main insulation of 12 rigid foam. I have planned vaulted ceilings throughout most of the house. There will be 8' ceilings for the middle 3 rooms (kitchen, bath2, and basement stairs). Over these 3 middle rooms I do not want to add extra insulation. Is there a technique or ducting method to provide minimal air flow over the middle section and not waste expensive AC?