We are using zabbix_sender to send data to Zabbix from a file with timestamps included for each value. We are sending those values in 20 minute intervals.
There are 8 hosts that collect these metrics, each one is set up properly and receive data correctly.

We want to get an aggregate item/graph for these items. The problem is that the aggregate item updates during the "Update interval". So one minute, there is no data for the last 20 minutes, then, once the script is run, there is data for the last 20 minutes. The Aggregate item then collects and sums only the last value. So the graph is just solid lines every 20 minutes.

I would like the ability to tell the Aggregate Item to recalculate the last X minutes of values.