Yes, you can buy a separating zipper just as you can a traditional clothing zipper. Go to your fabric store and browse through the zipper section and you will see them. You sew it in when it is closed, just like you sew in a regular non separating zipper. But with a separating zipper, there is a small metal gizmo that the bottom of the other side slides into and 'locks' into place to hold the ends together to zip up--exactly the same as you see on any jacket that has a full length zipper on it. As Lynnie said, they cost a little more, and most of the ones I have used have slightly larger metal teeth, not nylon teeth.