City Based Product Display

MayFlower1980
Tourist
6 0 2

I am in the process of moving my current PHP Laravel website to Shopify. 

I have a query regarding city based listing. 

I have about 100 delivery cities.
There are common products that are available in all 100 cities.
However, there are few products that are only available in say 10 cities or in some cases even less.
How do I segregate or display this?
I want the user to come and see all the products and when he wants to check out then select the city in the drop down (or pincode) and then add to cart. 
Is there anyway to get this flow?

Making Cities under Collection would be a cumbersome task and not the right way. I have almost 500 products on the site. Do I add tags (as Cities) for each product? This again could be quite a task as the number of Cities is large and would be time consuming.