You wont be able to use that in the use-case described in the OP.

One, you won't be able to post the encrypted messages before the "reveal date" because the owner of the public key will be able to decrypt it right away.

Another, sending separate encrypted messages to each participant where they are only one who can decrypt the specific encrypted message will produce doubt that you might have sent a different criteria to others.
They can compare it by themselves but that will also subject to trust that they will tell the truth to each other since the other participants can't decrypt the other participant's encrypted message.