How to specify a zeebe worker to do the task?

Imagine that there is a zeebe worker cluster, when deployment happens, there is a code change in the worker.
I want to deploy just one instance for the gray test. How can I specify this gray zeebe worker instance to pull the job created by itself?

What I think is when this gray instance creates a process instance, I will add a gray tag into variables or someplace, and this worker can only pull jobs with this gray variable, will it happens?