Lightroom does not allow a multi-user shared catalog. Lightroom catalogs cannot be on a network drive.
Your best option at the moment is NOT Lightroom. Simplest is to put your images on a NAS drive (many options for this but an attached drive to your Airport should work just fine even with raw files albeit probably a bit slow) and organize in folders and use Bridge to import, organize and edit in camera RAW and Photoshop. Lightroom simply doesn't work reliably in a multiuser environment. Some folks hack around it, but there are many potential pitfalls with this and you can really mess up your images so I'd highly recommend against it. You can in principle use Lightroom on your individual machines and set it up to automatically write xmp files and religiously read metadata from files on images others are working on but this has similar issues. Another option is to only have your editor use Lightroom and have the photographers ingest the images to folders on the NAS drive using native OS tools or Bridge and have the editor import (add photos or synchronize) those in his/her own Lightroom catalog. If the editor has automatically write changes to xmp turned on, you can see the images with changes on the other computers by opening in bridge in camera raw.
There are many options for NAS drives that work well. Make sure that you get a RAID array system or that you have a backup solution for it. I like the drobo systems for ease of use but they are not the fastest nor cheapest.