I see in the Help that I can have an external file with virtual machines listed that I can "Link to a Machine Group". Is the format of this file similar to a "regular" machine file (simple txt file with each machine on a single line)? The example in the Help lists the files with a ".vmx" extension - are these the actual vmx files used by VMware to run the machines?
I take it you are looking at the help for adding VM's under the "Workstation virtual machines" tab in the machine group, and the import from file option here is meant for offline VM's. That's why you have to specify the location of the .vmx file - we actually need to access this file to bring up the offline VM.
If you are just adding systems that will be online when scanned you can use a file linked to the "Machine name" or "IP Address/Range" tab, depending on how you want to list them in your file.