GROUP - Windows Contacts Group File is a very neat file extension that is made of up a collection of different contacts. These contacts happen to be created by Windows Contacts. This is a very handy program that is included with most Windows operating systems. If you need to download the file extension to enjoy more features and benefits, then you definitely have that option. You will also be able to add different contacts once you add groups, etc. Group files can be made up within this wonderful program as well. You will also be able to create different mailing lists through this program. This can be used for sending and receiving email messages. It is also very simple to ad various contacts when you need to the most.