Provide query instead of index name when generating recommendations

[pratikshya]

Would it be possible to give a query instead of index name alone when generating the recommendations? For example, in the code below: curl -XPOST localhost:9200/_river/movielens_items_from_user/_meta -d '{ "type": "taste", "action": "recommended_items_from_user", "num_of_items": 10, "data_model": { "cache": { "weight": "100m" } }, "index_info": { "index": "movielens" } }'

Instead of providing the index_info, would it be also possible to provide some query which will bring subset of the actual dataset? I do not want to recommend items for user from the entire dataset but subset of it. And having said that I do not want to have one index per user as well. Is it possible to use query as source of data instead of index itself?