You can use chopped ham or bacon also if you like you could make a diet pea soup by using bacon stock cubes.
None of these are as nice as the ham hock but the ham hock is going to take a long time whatever method you use and you can use it to make baked Boston beans with later .
If you have a pressure cooker you can reduce the time by over half of what it would take to boil. use some of the soup to cook the ham hocks and then return to soup.