one of the documented procedures in this installation of the ACS
im_groups_initial_list   parent_group_id
What it does:
Memoizes and returns a list where the ith element is the first initital of the group name and the i+1st element is the number of groups with that initial. Only includes groups whose parent_group_id is as specified.
Defined in: /web/philip/tcl/intranet-defs.tcl

Source code:

    return [im_memoize_list  "select im_first_letter_default_to_a(ug.group_name), count(1)
               from user_groups ug
              where ug.parent_group_id = '$parent_group_id'
              group by im_first_letter_default_to_a(ug.group_name)"]