Only look at data from 15 min chart?

 
I'm a little confused. Can someone tell me or show me some code snippets to do the following:

I would like to make an expert that would merely follow the trend based upon ASCTrend. Once a signal to buy or sell is generated, on a 15 min chart, as long as the current bar closes below the previous bar close, to continue (for sell, buy would be oppisite). If it reverses, I want it to close the order. It will of course open the orders every time a signal is generated, and exit as I have described. The trouble is it needs to look only at the 15 minute chart, not tick by tick data.

Also, I have a PivotPoint Calculator, and would like to know how to draw a vertical line at 12 AM EST, as well as calculate the Open, High, Low, Close values at this time, rather than 0 GMT, which the example Pivot Point indicator by MetaQuotes does. Thanks!