Answer: VLAN(Virtual local area network)
Explanation: VLAN(Virtual local area network) is the networking device that displays the flexible nature due to the logical connection of one or more LANs. VLAN is used for the purpose of the management, security, scaling etc.
VLAN also has the ability to provide the segmentation in the network by dividing the physical network into segments and making logical network. Router is the source for maintaining the communication in the VLAN.
Thus according to the requirement mentioned in the question ,VLAN is the network device that should be used.