You can create a FileVault Master password and distribute prior to enabling FV2. That allows for unified pass phrase.
JAMF allows for more options now with recent versions of the Casper Suite and Macs with 10.8.
I highly recommend reading over the articles posted by rtrouton at http://derflounder.wordpress.com and search on FileVault. You'll find everything from establishing the FVMaster password and recovering/unlocking.
I would not create a generic pass phrase with the idea of sharing it with others. You want to protect that from anyone or it will be shared world wide.