VBA to Sort Data and exclude the negative numbers with respect to time during averaging

I want to write a VB macro that can sort through this data and give me results as indicated in the result section. I will like the macro to take the result section to a new sheet. I have put in the result section here in the same sheet so that you can easily see how the equations are referenced.

Below are my objectives:
1. First split the date so that the time can be separated as you can see in the result section were we have date and time -- no longer joined together
2. For Data AI in the result section: Take the average of the data but exclude the negative data during the average. If all data at that time frame is -999.25 or negative, please return zero.
3. Let’s take a look at the result section, Cell K8. We can see that it averaged the time for 8:16 (11/21/2013) and excluded the negatives.
4. The same concept goes for Data AL, AJ and AK.

Hence I want the macro to sort through the data, extract the time in separate manner, and correspond the time with the actual data (excluding the negative averages). And take the results to a separate sheet

I have put in a formula in the result section to help you understand how I want the results to be.
Thanks for your time