Using metrics to create a variable

I have several Citrix VDA servers that are now shut down but may be started in the future and I don’t want to see them in dashboards. How do I create a variable that looks something like:

show tag values from “win_system” with key=“host” where host=~/CitrixVDA/ and host.system_up_time >0

Version of grafana?
Data source?

Version 8.4.3 - using telegraf to pump data into influx