Hi @LoHey , welcome to the Community!
To answer your question: unfortunately, you will need to. See the docs here . As of today, there isn’t the sophisticated topology routing capability which existed in our Direct Messaging only equivalent: MNR (Multi-Node Routing).
To quote:
It is not necessary for each cluster to be connected to every other cluster; however, messages only propagate between directly-connected clusters.
What are you trying to do / achieve? Why don’t you want to link them? Perhaps there is another way to accomplish the behaviour you seek.