EA to average in to position

 
Does anyone know where I can get an EA/ utility for mT4 that will allow me to average into a trade. So for example I want to enter a trade with a 50pip stop, I enter the first market order, then the EA/ utility enter another one for me at -30 pips, the stop for both is set at -50 pips. Does this type of order entry average in utility exist?, ideally one where the average in disatnce and stop levels can be altered according to the trade setup