Source: http://lifehacker.com/5603492/create-a-better-emergency-contact-number-with-google-voice
Use an extra Google Voice number to make an In Case of Emergency contact number that dials multiple family members at once.
A lot of us have more than one Google account (in fact, Google just launched a new feature specifically for multiple account owners), so the idea would be that you set up one of your non-primary accounts with Google Voice, then make that number, when called, ring everyone you'd consider an emergency contact—maybe your significant other, your parents, your sister. The only caveat:
While Google Voice allows you to use two Voice accounts for the same number, you do have to trade off features. That is, let's say your significant other already has a Google Voice account. If you created a new Voice account and set his/her number to ring when that Voice number was dialed, you could do that. But they wouldn't be able to use SMS with their default Voice account. (Then again, if no one you'd list as an ICE contact uses Google Voice, you're in the clear.)
It's a clever idea, and one you could also incorporate with the ICE contact you've already added to your phone.