It's easier to be explained with an example:
Let's say I have a warehouse. My models are Order and Item.
The Order business logic is described in an FSM with states like: PendingPayment, Paid, PickingUp, PickedUp, etc.
An Item also has an FSM with states like: BackOrdered, InStock, Collected, Packed, etc.
The problem is this:
The Item has transitions that depend on the state of the entire Order. For example, transitions to BackOrdered and InStock depend on the Order being in the Paid state. Collected and Packed may be relevant only when Order state is PickingUp.
Hierarchical State Machine doesn't really fit here, since the Item state is "spread" between different Order states.
Any good ideas how to approach this problem?