Lock other fields when certain option in a Dropdown Option is selected

PharaK SupportServiceManager

My Form has

Dropdown Field Options 1. Debit Order 2. Cash

Other Fields: Account Number; Bank; Debit Date

Is there a method to Lock the other fields in the form when form user select the Cash Option. 

The form users always ask why they need to enter Account Numbers when they have selected Cash Option. I want the Debit Order fields to be Blocked or Greyed Out or Disabled when Cash option is selected. 

Current solution I have entered a note in the account number field for the user to enter 0000 if Cash option is selected. It's working but it would be nice if the cells are automatically disabled. 

Bruce Case

I hear conditional Forms are in the works.  I vote for that.

As another possible workaround that we have for something similar, you could have 2 forms, based on the FOP.  With that, you could have the appropriate required fields for each.  Again, perhaps not ideal, but another option.