OptionalbaseIndex of the base (source) cache field that this grouping is derived from.
OptionaldiscreteDiscrete grouping: maps each shared item index to its group index.
OptionalgroupThe group item labels, representing each group's display value.
OptionalparIndex of the parent grouped field (for multi-level grouping).
OptionalrangeRange grouping properties (for date or numeric range grouping).
Field grouping information that defines how a cache field's values are grouped.