Is this going to be a still cider, or carbonated?
'Cause if it's carbonated, then yes, you need to worry about it pushing the corks out. You can do a wire cage like the top of a champagne bottle, but that does require extra long corks that have bulbous ends on them. I don't know the specifics, but there was an article in BYO a few months ago. I can't find it on their website, but good luck.