Is there any way to use the search result from one index to search on another index?

Elastic Stack Elasticsearch
1

I wanted to search for some data on the first index.
Then I need to find the unique values of a specific field in the above search result, and search for the them in the second index.
The names of the indices are different.
How can I do this?

Thanks

2

You need to issue two separate requests. It is not possible to do tjis in a single query.