when you are using the eZ Webin toolbar (front-end editing) there is an icon called "add location". This will let you publish the article in multiple locations. You can publish it in as many locations as you want.
You can also do this in the administration interface when viewing an object. If you enable locations (by clicking on the tab in the top middle section of the screen) you can manage the locations an article (or any object) is published to.