This FAQ answer assumes that you are using calibre's hierarchical items as described in the calibre manual section Managing subgroups of books, for example “genre”.
The answer: yes, partially. CC supports a two-level hierarchy. The second and later elements are shown as a single item. The following image shows the effect. The outermost item "AA" is on its own line, with another line for every subgroup no matter how many levels are in the subgroup.
The groups that show hierarchy are selected in CC in Settings / Grouping Drawer / Hierarchical Groups. Changing this list will cause CC to go through a "Database upgrade" in order to build the needed information. The upgrade can take some time, perhaps 1/3 to 1/2 second per book in CC.
Hierarchy is shown only if the "Group by first letters" box is checked.