Nulifying resource requirements

[AgnosticMonk]

Is there a way to make it so that instead of resource requirements, have it implemented where it takes more to build the units without the aforementioned resource? Many of the resources required to build units were hardly absent in most given territories, its more a matter of whether they were easily accessible and in concentrated quantity (well, that and if the civilization knew to use it). For goodness sakes, the mines in hills without resources aren't exactly pulling up nothing but candy canes and lawn gnomes. It'd still be of major benefit to grab a resource if it took 50% or more to produce units that required those resources, as quantity certainly means something in war, but its ridiculous to think that there might not be a drop of iron in a whole continent and thus no swordsman to protect it.