How do we make the Salary Amount "read only" via Visual Builder?

Summary:

We need to make the Salary Amount "read only" for Add Pending Worker, Change Assignment, etc. using Visual Builder for certain roles. We only build Salary Amount based off of Position grade steps in our organization so we don't want the other options available to use. We tried to change it to read only these field via configuration, but it is locked down for editing as delivered item.

We were able to do this in RUX via Page Composer but it doesn't seem like we can do this via Business Rules in VB

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