Yes you can. Bring them to a shop, and they can replace the edge for you. Might be pricey, and it looks pretty rough, but if you really want it done, its more than possible.
If it's for rails, there is no point. A guy I work with replaced 3 edges underfoot, about 12 inches each and one fell out on his first run. We've done it for snowboarders and it's alright for them because they're more flat base on rails. You could get the edge replaced and then just use those skis to cruise on. Otherwise just round off the ends of the edge at the gap and coat the gap with epoxy.
ya you can but if you are using the ski for park it might not matter...you can buy then here although instlation is sometimes tricky depeinding on what type of construction your ski is(cap or sandwich)...