Yes, there is group policy settings for FileVault in the MAC OS x Settings | Preference Manifests | Mobility and Time Settings.
In order to use File Vault with AD users, they need to be activated as Mobile Accounts. To enable an AD user as a Mobile Account, do the following:
Login as the AD user in question
Open up System Preferences
Click on Users & Groups
As an Administrator, unlock the lock icon on the bottom left
Where it says "Mobile Account:" click on "Create..."
Adjust settings as required, then click "Create"
Click "Create" again
OS X will then ask you to enter the password for the AD user
To configure FileVault for use with a Mobile Account, enable the user as you would a local user.