Final answer:
During data communications, a host may need to send a single message to a specific group of destination hosts simultaneously. This message is in the form of a multicast message.
Step-by-step explanation:
The type of message that a host may need to send to a specific group of destination hosts simultaneously during data communications is known as a multicast message.
In the given scenario, the message route is similar to sending a message remotely to communicate with people in a remote part of Earth. Instead of physically traveling, the host can send the message to multiple destination hosts at the same time.
This form of communication is commonly used in computer networks, where a single message can be sent to a group of hosts that have expressed interest in receiving the message.