Using global variables across YAML files within Artillery

Is there any way in which I can say, define a URI that will be used in different .yml files for different Artillery load tests?

I am wanting to use the same URI within a number of .yml files to define the target within the config section.

I saw the following on the Artillery docs:

Values can be set dynamically via environment variables which are available under $processEnvironment template variable.

For example, to set a default HTTP header for all requests via the SERVICE_API_KEY environment variable

They show an example doc of:

export SERVICE_API_KEY="012345-my-api-key"

artillery run my-test.yml

However I am unsure of how to implement this, as I am using the package.json file to run the artillery run my-test.yml command.

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