Group metadata consists of the standard container type project and the container ID.
Note: Metadata name-value pairs are case-sensitive.
To limit a rule to a particular group:
Click Edit next to the Metadata field for the rule.
Click Add Metadata
Add the name-value pair containerType=project and the name-value pair
containerID=containerID. You can find the container ID for a project by navigating to the project, starting to create content there, and then copying the number after containerID= in the URL.