Opencart modification

We have opencart store in which we would want to implement certain features : Its a pharma store - we need following functionality .. When customer enters to site he selects a product , based on product he has selected he will get a questions list to answer or select from the answers based on that he can either buy a product or he will be sent to doctor's page to consult so the front end will have above functionality where backend will have admin section with all ecommerce modules and and additional module of questions and doctors associated with each category of medicines..