Create index in which one field as an Object of not same structure

So i need some suggestion , in my project there is existing sql table .in which i have some fields and one nested object. that nested object i am storing as json string and i am querying on that. and main thing is that object is 10 different structure any one of them can be used at a time to store.
so now we want to change the database to Elasticsearch. for that i need some suggestion like how can i store the data by creating single index, or can i create multiple index for all 10 object and then add the table fields in all the objects. or create a single index. the most important this is that i want to run the query on that nested object for some nested field the objects are complex one