Display ics groups

organize calendars in groups that contain more than one calendar

in mac ios http://www.macworld.com/article/1054445/icalgroups.html and with pic http://www.dummies.com/how-to/content/how-to-group-ical-calendars-in-mac-os-x-lion.html

List of applications with iCalendar support http://en.wikipedia.org/wiki/List_of_applications_with_iCalendar_support

maybe Drupal with its event module Joomla there are several plugins available

phpicalendar.net http://wiki.davical.org/w/PHPiCalendar several instalation with several conf files