Can we use Start/End times from a query to get duration to use it in another search query to get an average of a field in that duration ?

I am able to get the Start/End times of a load test execution from a search query (by getting End time from Timestamp (field) of the log data, and subtracting the duration (field) to get Start time. Now I want to use this Start time, End time and duration between them in another search query with a different sourcetype such that it would fetch all the data inputs falling within that time duration (between Start/End times) from another app logs - to calculate the average/count of a field. So, please help me in achieving the desired data with the required search queries (using subsearch/joins etc.)