You could make custom emotions for each, with IDs like
%bd:r%,
%bd:w%,
%bd:b% and
%bd:y%, and then make a script that sends
%bd:?%, where
? is replaced by a random letter (maybe using Math.random() and an array).
js code:
var Letters = ["r", "w", "b", "y"];
function OnChatWndSendMessage(PlusWnd, Message)
{
if (Message.toLowerCase() === "/beaddraw")
{
return "%bd:" + Letters[Math.floor(Math.random() * 3)] + "%";
}
}