Not sure if being idiotic or just not possible, but I am trying to insert custom formatting into a cell so when I enter a set of 9 numbers for phone numbers in the U.S. and 14 numbers for international phone numbers, it will automatically display it in the correct format. Reason for the 0's on the international is because country codes often start with a 0, so I need to ensure it isn't removed from the number. Any ideas on how one might be able to do this would be appreciative, this one is stumping me.

United States Format: (###) ###-####
International Format: 000-000-0000-0000