A group is a set of elements or other groups (or both)
  that you can combine and manipulate as a unit.

  For example, you might create a group that contains all
  the elements that process error messages; or you might
  create a group that contains all the chapters in a book.

  A group name is a string of 39 or fewer characters that
  consists of letters, digits, underlines, hyphens, or
  dollar signs.  Periods are not allowed in group names.

  You can perform the following functions on groups:

  o  Create and delete groups
  o  Fetch, reserve, replace, review, and set an access
     control list (ACL) on the contents of a group
  o  Insert elements (and other groups) into a group
  o  Remove elements (and other groups) from a group
  o  Set or change the attributes of a group
  o  View the contents and attributes of a group