If the stocks which corelate with nifty are up/down ( >,= 4) then I continue the position, I won profit with one long and one short position. When the stocks which corelate with nifty show a change in trend, ( this happens 3 hours to a day earlier) in the 5 minute chart, then I alter or reverse the position depending on the %. I studied the system for a week and can see the logic.I would recommend that you follow the graphs for a week, and then depend on it.Remember that the corelations change everyday, which means everyday the stocks that move before the nifty are not the same. It seems to be simple statistical system.I kept the short position from friday because of the graphs, and looks like it was right too.
However, after 12.30 I also look at the dax and the ftse graphs to see what is going to happen in the westerm markets. hope this helps you.