Hi James!
Can you see if you can specify some rayStartParams in your values.yaml like this? kuberay/docs/guidance/rayStartParams.md at master · ray-project/kuberay · GitHub and set the groupName/resources to the one you want (workergroup-1)?
There was some more discussion about it here: Kuberay: run jobs in specific worker groups maybe some of the solutions discussed there will be helpful 
Lmk if that helps!
Christina