Security Zone - Cross Zone Group is used for?

To avoid false alarms when some of your zones are being too sensitive, you can join few zones in to the one "cross zoning group". In this case, when some zone within a group is being tripped, instead of triggering an alarm, it just starts counting "cross zoning time period" in which some other zone from this group should be tripped too. This way the second zone will confirm the alarm event from the first zone, and the alarm will be triggered. In case that cross zoning time will expire without some other zone is being tripped within this period, alarm event will be considered as false.