Chainlink multi-variable responses - is a single request returning multiple variables supported

The (legacy JSON format) example job-spec for Chainlink multi-word responses implies that a request is needed per item in the response. I.e if you have an API that returns all 3 values you're interested in within a single response, you need to call the API 3 times to correctly obtain and return the 3 values, as opposed to calling it just once and stripping out the 3 values from that single API call. Is this a limitation of the first version of multi-variable responses, or can the job-spec be created in a way to only require a single API call?