I usually do it in Excel but it is not easy for me to do it in KIBANA as well

I have this table in Excel and every hour I want to average for all instancs in the fiels "detail" but excluding the lowest three values (nine details each hour, the average should be only for the the six highest of them). In Excel I use the LARGE function.

The average here is calculated for the top 6 values of bytes only. Here are the settings:

You can try replacing the clientIP here by details and bytes by CPU load