Pending order on Mt4/MT5 alert?

Is it possible for me to automatically open a pending order on MT5 alert? I want to put a buy/sell stop order when alert goes off.

Scenario is this - current price is lower than price I want alert to go off. when alert goes off, I want to place sell stop order at 15 pips below alert price. how to do this? I am not always
at computer.

thanks
Sal