How to connect two clusters in different VLANs? Or make one cluster over two VLANs?

To train, we made two clusters over several stations. All the nodes could be in the same subnet, but we made one cluster in one VLAN, and the other cluster in another VLAN. How could the two clusters work together?

Maybe what we are trying to do without knowing, is to have the same cluster over two VLANs. But in Calico, the Cidr can be set to match either one subnet or the other. Is there a way to jump over subnets in order to have all the nodes in the same cluster?