"Phases" for onboarding journeys

Summary:

Is there a way to create a "phased" Journey? I am wanting to create a journey that is under the "onboarding" umbrella that will have tasks that assign when a candidate is moved to HR, then ones that open on their start date and then still more that will open, say, a week after start date.

I thought task group was the key, but you can't use task groups in onboarding checklists.

Is there another way to accomplish this?

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