Create a form for a specific Additional Earning?

We are creating a form that is specific to one Additional Earning, its purpose is to only show that specific earning. We can obviously "hard code" the account to be "Earning3" or whichever. But obviously its possible that certain Entities will have tis specific earning be under a different number if that entity does not have the other earnings configured.

Is there a way to pull just the specific Additional Earning, instead of hard coding the account?