Cash On Delivery Restricted To Postal Zip Codes

Hello,

Is there a way to use the "COD" (cash on delivery) zencart native module for a given set of postal zip codes?

The real life situation is as follows: at checkout buyers residing in Manhattan (that is all Manhattan postal zip codes) should be presented with the option to pay "COD;" while, for all other customers anywhere else in the world and even neighboring places like Brooklyn , the option to pay "COD" does not appear at all.

I understand it's possible to set specific zones for the "COD" module, like for example a "New York" zone, but New York is a big place.... I am trying to figure out a way to have the zone be a set of specific postal codes (namely Manhattan zip codes), instead of a wide area like an entire US State.

Any help would be greatly appreciated

postal zips are not part of the default code
This would require custom code to effect