Disable Receiving of ToGuilds For a Player

[ffcmike]

I have toguilds going into a scripted message box, which some players find useful for events, though it seems most players overall prefer the original method of receiving a PM.
Ideally I would be able to allow players to choose one or the other, but as far as I know, the only way a toguild can be prevented is to prevent it from being sent in the first place by capturing the chat, which means that it's impossible to give a choice as you have no control over receiving it.