How can i group data by 1h without taking the current time using stackdriver

I’m using stackdriver to connect to GCP metrics from Grafana. I’m not able to control the output data in Grafana as un example.

In this image when I change the time window the data changes.
I need data evey 1h, but the 1h go with current time for instance if time is 11:26 , data will be group as 10:26m,9:26m …
To fixe this probleme i musyt add this in time wondow:
But in alert i can’t do it , more than that i can’t add within as in this query by default

| group_by [] 
| every 1h  
| ratio
| mul(100)

 | graph_period 1h | within d'2023/09/28-04:25:31', d'2023/09/28-11:00:00'

Thanks for you help