Flows calling Crews or Crews/Tasks calling Flows

I’m trying to understand the relationship between crews/hierarchies/tasks and flows. Specifically, all the examples have flows calling crews, but can a crew or task call a flow? Is using a flow as a “tool” a valid usage pattern?

Generally you use flows as a control structure for your workflow. That means one flow with multiple crews being executed conditionally

My situation is that I want to have input determine which one of a few processes to kickoff. My original thought was this was a hierarchical crew, but now I’m confused. Is it required that flows are the outer most layer?

You can have a routing/classifier step in the flow that determines which crew to run based on the input

It seems like using the hierarchical process for that selection is the wrong choice.

In my case I need to select which flow to call. Each of the options has a distinct flow.

any documentation or working example?