I love the metal separating zippers for handbags!  It's great if I can find the correct size, but they are also very easy to shorten if necessary - just zig zag in place very carefully across where you want it to end and trim an inch or so below that.  You can also purchase little clips made to put across the teeth to make a stopper. 

We only have one of many of these colors, so be sure to get the ones you might be using before they are gone!