Hostnames: VM node-A, VM node-B, VM node-C
Adapter 1: Host-only Adapter (VirtualBox-Host-Only Ethernet Adapter)
Type -> Paravirtualized network adapter (virtio-net) - Deny Mode
Adapter 2: Bridged Adapter (Intel Ethernet Connection)
Type -> Paravirtualized network adapter (virtio-net) - Deny Mode
Test
Try to connect one of VMs such as "node-A" by SSH