Special shipping for some products in a zone

I have 2 werehouses in two cities, the main werehouse have all the products, but the secondary werehouse has only some products, special for local shipping

I need to be able to offer a special (local) shipping but some on selected products, so If:

• the user is located in one city (zone)
• AND the user selected some of the special products
  the special local shipping should be offered

do you know any way to do this?

I was planning on make "free" shipping for this products with the local shipping price included but then I should be able to restrict the product for just the clients of that zone

At this time there isn't anything built into Zen Cart to manage the shipping on a per product per location basis ...

This would take quite a bit of coding to work this up ...