Hi,
When you know the sequence numbers for all orders, you can use "AssignmentRule set to (1) Preserve route and relative sequence" to lock Depot B as the second last visit in the route. However, if you don't know the sequence numbers, VRP solver cannot solve your problem directly. There is a workaround for it.
You can use Depot B as the end depot for the route. This solution will not include the part traveling from Depot B to the end Depot A. If you want to include this part in the solution, after solving the VRP layer, you may load Orders and Depot Visits into a route layer as Stops in the sequence created in VRP layer, and add a copy of Depot A as the last stop in the route layer. Solving this one will return you the complete route.
Thanks.
Anna