Update Instance level properties from propertysource

I am working on an integration utilizing autoinstance properties. I am adding instance level properties to custom discovery scripts which end up in the json payload when an alert is triggered. I use the property to escalate to different teams in the organization. This is based on 

https://www.logicmonitor.com/support/datasources/active-discovery/script-active-discovery/ 

The issue I am running into and thus the feature request. I would like to have an instance level property added automatically to built in data sources where I don't use a custom discovery script. One datasource I use is SQLServerStatistics which does auto discovery via perfmon. There is no way for me to add a property to the datasource or discovery instances. Currently we can add auto properties to devices themselves via PropertySources but thats as granular as I can get. I could do this with the api but then there is a lot more management on my side of things. 

It would be nice if I write a propertysource to update/add an instance level property like you can with a custom discovery script.