View sorted by custom fields

I would like to create a view that sorts users by whether or not a custom field is filled out. Currently, it is not possible to sort a view by multiple custom fields. You can sort by 1 custom field, however this will only sort into the field options if a dropdown, or if it is filled out or not. 

The only way to do this currently is to create multiple views with different settings. Unfortunately this has the potential to really clutter the views menu, creates additional work and will add more time to tasks. 

Example.

Say I have end users that go through a process which includes 4 steps. I would like to have a view that is sorted into these 4 steps, with the users in their appropriate section. 

If a user is in Step 1 and the Step 1 field is filled in, they are only under the Step 1 section in the view. Once they move to Step 2, Step 1 will be changed to a blank option, and Step 2 will now be filled in. Once done, the user should now be under the Step 2 section of the view. Continue with Steps 3 and 4.