Adding upper and lower kill zone bands to an existing ea

i have an ea that was made about a year ago. it works by creating a pair of buy/sell trades with the same lot size. the ones in profit are closed by psar, the loosing ones are partially closed.

so there is always a grid of loosing trades open which creates a blanket of trades just waiting to be harvested by the psar.

what i would like is an upper and lower level around 500 pips that follows the price line and closes any trades that are touched by either line. so only the trades within these bands are left open.

the ea already has a button so this can be done manually, id like to see the effect of it being handled automatically at a fixed distance 

as always times and cost is open to discussion,