What is the right way to intercept a flow and redirect the user to a different state?

I assume I will want to use FlowExecutionListener. I'd like to be able to signal a new event, regardless of what the user was doing. This looks like I want to use the resuming() method but I'm not sure how to signal an event when I just have a handle on the requestContext.

The scenario is, we have a large flow that is manipulating a particular object. This object has its own internal state that we manage as the user goes through the flow. It is possible for the internal state of this object to be changed outside of the flow, by a different process. We need to be able to detect this change, and redirect the flow user (I assume signal a new event) to a different flow state.

Thanks.