I see, thank you for sharing.
I’d suggest that this is perhaps best done by tracking it at the Client level. Depending on your current approaches to patch deployments, there’s at least a few different ways you can do this whereby you leverage an actionscript to output the current Relay to a tracking log file on the endpoint, which can be parsed by a property for reporting purposes.
How do you typically deploy patches? Do you typically leverage baselines, or single action deployments, or Patch Policies?