This question is an exact duplicate of:
i am working on a medical site. i have 3 content type drug, pharmacy, drug price.
to enter the price of a drug for a pharmacy i use drug price content type
here i take a reference of drug content type for drug name and it is working fine and populate nodes title of drug type
and after that i want to add this price of drug to any particular pharmacy, because i have many pharamcy with the same name in differen area. so i want two add two fields in drug price content type, one for zipcode and another for pharmacy title. both of them are already there in pharmacy content type . so i want that entity refernce populate only the pharamcies based on zipcode given in the upper filed by admin.
please check the screenshots