Forums Scripts & Popups Automatic answers only one time

Hello all,

I'm looking for some idea to send only one time a automatic
answer on a query.

If I use the classic :

on *:TEXT:*:?:msg $nick excuse me , I'm busy ; for example

The trigger start every time $nick send me something.

I want send the answer only one time , eventually with
different answers for different nicks.
How may I do this ?

Thanks all.