konserw
Chieftain
It's ok for me 

Good suggestion, but above what a mere map maker like me can do. ^^
If the ViSa team would apply such a python solution, I'd surely use it ^^.
My suggestion on this would be to change two "files"
a) design a python that can place additional resources if the following conditions are met
1) the resource can only be placed in the old world if it is a new world resource, and vice versa
2) all climate restrictions apply
3) resources can only be placed inside the cultural border of a nation that has access to that resource already, either due to a colony, or due to trade
4) resources can only be placed if there is a building using that resource (stable and such) is "nearby"
b) Change the terra map script to include a requirement of "new_world" or "old_world" for certain resources additional to the climate limits. So terra maps would be even more similar to real terran restrictions. And if you are at it: five civs a flag about their origin, so that placement would be a bit more realistic ^^.