Search geoData from another index in Elasticsearch

I have an index (called "businesses") that contains businesses. These businesses have geoData on them specifying where the business is located.

I have another index ("items") that has things these businesses are selling.

Now I want to restrict the search of items being sold through geoData of the businesses. For example, show "mangoes sold by businesses around 221B Baker Street". This should restrict the search of mangoes to businesses around 221B Baker Street.

How do I solve this problem in elasticsearch?

Question also at:

Well you cannot join between indices, so you would need to attach an item tag to the business.