Working with Outlook
You'll probably want to use a subset of your contacts for most mail merges, but there is a problem. Word won't recognize your Outlook filters. And using Word's built-in query capability probably won’t work either, because it won't recognize all of Outlook's fields. So what do you do?
First filter your contacts in Outlook, create a new folder, and copy the filtered contacts into that folder. Then, in Word's Mail Merge dialog, select this new folder as your data source.