Limit Dropdown Choices from Reports

Yes but this is not intuitive. You first need to make a new form on the child table - I would call it something like 'Grid Edit Form For xxxx Report'. On this form put all the fields you want the user to see when they grid edit. Typically, you just use the same fields that are already presented in the current grid edit, but you can choose any. Be sure your dropdown selector is there, and choose the filtered report.

Then on the forms settings page, expand 'Override Settings by Report'. Find the report that the user is grid editing (the one where the filters do not exist), and under Grid Edit Settings select the new form you just made (Grid Edit Form For xxxx Report').