You only need one Header declaration, to add multiple Vendor Names under this. You can see this by Exporting from any Sample file, or even your own. File menu > Utilities, Export, Lists, Vendor list. Then, open it using Excel.
One row for !VEND simply defines which data is in which sequence for the fields
Each actual name and info is the VEND line, one per line.
To learn, it helps to Export and look.