Say you have a text file with a bunch of HL7 messages. Each segment ends with \r. And each message ends with \r\n.
You could use the simulator component - but honestly it’s probably easier to write you own little component that have a custom field for filename, can read in the messages, split them and push them into a queue.
Then it’s super easy to push test data into your interfaces from that - more straightforward that other techniques.