That's fair. I guess I'd do a couple of things to improve the situation. As the curve between the two is completely arbitrary, I'd make it a straight line to make it more obvious that it is a conceptual separation of the two. That's completely optional. The second thing I'd do, and is more important is to add ref= tags to  the different fairways. Tools that see adjoining fairways and roughs would see them as the same and try to combine them. Since there is a valid reason to leave them separate, tags would help make that clear.
