I’m not sure if I fully get the use case, but for any cloud resource other than VMs/EC2s/Compute Servers, you should be able to assign a local collector from the resources page, which would allow you to create a PropertySource that runs on the local collector to add any properties that you’d like, which doesn’t necessarily require calling the cloud resource.
The difference with VMs/EC2s/Compute Servers is that you’ll need to assign a local collector from the cloud integrations page, which uses the defined Public/Private IP address for built-in collection methods such as WMI/SNMP/Ping etc.
https://www.logicmonitor.com/support/lm-cloud/monitoring-lm-cloud/enabling-cloud-resource-monitoring-via-local-collector
If you want to run the script somewhere else other than a local collector, you can use the API to set/edit custom properties as needed within the script.
https://www.logicmonitor.com/swagger-ui-master/api-v3/dist/#/Devices/patchDevicePropertyByName