Outputting to several elastcisearch indeces

I get JSON document to logstash. I write them to elasticsearch (it is log data).
I'm wondering If I can write these documents to several elasticsearch indeces.

I'd like to write the whole documents to one index, and only certain fields to another.

Example:

{ user_id : 12, user_data: {some_object}, timestamp: 123131323 }
To first index goes all fields (as it does right know).
To second index goes only user_id and timestamp fields .

Is it possible ? Example of logstash.conf would be really great.

You will need to clone the events, then drop fields as appropriate and finally send them to their appropriate indices.