Sorry for the delay.
I was looking through the GameplayStatics to see if there was a travel function exposed to blueprints. I’m told there is, but I haven’t found it yet. I see OpenLevel, but I’m not sure that is going to do what you want. It calls SetClientTravel which would move a client to another server, but I don’t believe it will take a server and bring clients along with it. You could try that for now and see what happens.
It is already on the roadmap to make travel/multiplayer a lot more friendly to blueprints.