Automatically updating list from another list in child site

I have a list called 'Mobile Phone Tracker' in my subsite with employee name and mobile numbers and other details. I need to create another list 'Mobile Phone Directory' in my site (parent site) with only name and mobile number which can be used as a mobile phone directory. The new list must update from the 'Mobile Phone Tracker'list automatically as i update it. Can any one help me with this. Thanks.