I know that post moderation is possible with membergroups, but is it possible to set it up so that any post made in a particular board needs to be approved before being visible to the public?
You can do this using local board permissions :).
See:
Boards (http://docs.simplemachines.org/index.php?board=55.0;sort=subject)
Permissions (http://docs.simplemachines.org/index.php?board=60.0;sort=subject)
Thank you very much H. That solves my problem. :)
No problem. Glad you got it working :D