Backtesting fucntion

I'm working on my cBot via cAlgo. I want to run my backtest at some specific time of the day (i.e. 8:00am to 12:00am) but for now, cAlgo only allow backtest run form day to day. If i could choose time in a day to run backtest, or there is anyway to track the time of a specific candle.For example, i can get the data of open time of the first candle in the day by marketSeries, but I think it could be better if i could get the open time of a specific candle in OnBar(), which will be great for backtesting. Not sure if this option is not available, or just I don't know yet, but just put it here.