I am looking to play a variant of Diplomacy over email or other messaging system. The specifics of Diplomacy and of the variant are not important, suffice it to say that the root trouble is simultaneous moves.
Consider scissors-paper-stone as an example: how would you play that over, say, email? One possibility is a neutral person. Both players email their throw to the arbiter. He holds the first email until he has received the second, then he forwards each email on to the other player.
This neutral person could be replaced by a computer, as this function is pretty brain-dead.
I am aware there are services for online Diplomacy (and scissors-paper-stone for that matter), but they are specific to that game. The variant I am looking to play is not supported. I am also aware that this could be done using cryptographic hashing, but there are practical issues with that (like player education).
Is there a simple service that just collects messages from a given list of recipients, and then forwards all messages, unaltered, once it has received a message from everyone on the list?
This can be over any internet messaging system that would not require too much player education. (EDIT: I meant to include things like web interfaces also, as long as they're easy to use.)
It seems like the sort of thing someone would have already come up with.