As you have seen, you can use the technique shown here to process any human-readable input message in Iguana, whether it is in HL7 format or not. You can use this technique to process more complicated streams of messages:

• If your message stream contains one type of message, but the message contains data in more than one format, define a different custom segment for each data format. For example, you can define the ZSD segment for one data format and the ZSE segment for another. Then, in the Global Inbound Script in your VMD file, write Python code that determines the data format of each line of data in the message and adds the appropriate custom segment name.
• If your message stream contains more than one type of message, you will need to write Python code in your Global Inbound script to distinguish one type of message from another. You can then define one MSH segment for each type of message, using the fields in the MSH segment to differentiate one segment from another. In the VMD file, you can then create a message definition for each message type, using the fields in each message's MSH segment to sort out which messages are to be processed by which message definition.