Note that the first two albums released by the group, as well as the majority of their singles, were not credited to "The Highwaymen," but to 'Waylon Jennings, Willie Nelson, Johnny Cash, Kris Kristofferson'.
Here are their first two albums:
Waylon Jennings • Willie Nelson • Johnny Cash • Kris Kristofferson - Highwayman
Waylon Jennings, Willie Nelson, Johnny Cash, Kris Kristofferson - Highwayman 2
Here is a compilation:
Willie Nelson, Johnny Cash, Waylon Jennings, Kris Kristofferson - The Highwayman Collection