Get unique values of a field from the list of documents in CMS


I have added a new controller to my project to fetch all the articles and display authors and other metadata as list ranging from A to Z.

Below is the code snippet:
letter can be any single character from A to Z

hstQuery = ofTypes
and( constraint(HBG_RATING).lessThan(“5”),

			HstQueryResult result = hstQuery.execute();

And then I am just using HippoBeanIterator to iterate over each document, fetch the field reviewer and store it in a map.

The problem here is the limit. The default limit is 1000, but I have more than 1000 documents with Reviewer say R which also includes duplicates.

For example, I am getting 500 documents with the same reviewer RK instead of 500 different reviewers.

Is there a way to update the query to return documents with unique reviewers or is there a way to just return unique reviewers from the CMS?

Hope I am clear. Thanks in advance.