transportation cost

I am working on a project which is being designed for a south pacific island. The majority of the construction materials do not exist on the island with the exception of rock. Fortunately, our facility's structure will be made with a cast-in-place concrete frame which will be able to use local aggregate as the primary constituent. Unfortunately, the cost to bring the remaining materials is very expensive due to the extreme transportation cost despite their relatively inexpensive material value at the point of sale. The aggregate we will use, being local, is of course very inexpensive since its value not inflated due to travel. The question is: Would it be acceptable to value all of the materials according to their point of sale purchase price and ignore the transportation cost, much like the labor cost, or is the cost of transportation to be included as integral to the material cost? Obviously, our calculations would benefit greatly by being able to include the largest componant of the primary material as a regional material if it were not for the fact that it has a negligible percentage of the overall inflated cost.