There is a network with five nodes on one interface. These nodes should not be accessible to each other. An option is to use an ACL, but is there another way?
If the hosts are in the same VLAN and the switch they are connected to support it, there's a feature made precisely for this case: private vlan
This allow the devices to communicate with remote networks but not with each other.
As explained in the linked article
private VLAN is the name of the feature in Cisco world. Some other vendors have the same feature with another name, mainly