This feature was added in KReporter 4.1.
The Bucket Manager allows to group records based on enum values or text fields in different buckets.
For example, you can take Opportunities and group stages into the 3 buckets Open, Won and Lost. Then you can assign existing stages to the groups and report only on the new buckets. Buckets can be used for display but also for selection purposes. A quite powerful tool to summarize and structure reports.
Following steps describe how to create the 3 buckets in our example.