How to Limit 'Sort By' Fields to Specific Fields in Acumatica Mobile App Screen?

Recently, I added the Invoices screen (SO303000) to the Acumatica Mobile App. Can you please guide me on how to limit the 'Sort By' fields to specific ones, such as Type, Reference Nbr, Date, and Amount? Please see the screenshot below.

Here is a part of my code related to this.

add screen SO303000 {
  add container "InvoiceSummary" {
    add layout "InvoiceHeader" {
      displayName = "InvoiceHeader"
      layout = "HeaderSimple"
      add layout "InvoiceHeaderRow1" {
        displayName = "InvoiceHeaderRow1"
        layout = "Inline"
        add field "Type"
        add field "DetailTotal"
      }
      add layout "InvoiceHeaderRow2" {
        displayName = "InvoiceHeaderRow2"
        layout = "Inline"
        add field "ReferenceNbr"
        add field "LineDiscounts"
      }
      add layout "InvoiceHeaderRow3" {
        displayName = "InvoiceHeaderRow3"
        layout = "Inline"
        add field "Date"
        add field "DocumentDiscounts"
      }
      add layout "InvoiceHeaderRow4" {
        displayName = "InvoiceHeaderRow4"
        layout = "Inline"
        add field "Status"
        add field "FreightTotal"
      }
      add layout "InvoiceHeaderRow5" {
        displayName = "InvoiceHeaderRow5"
        layout = "Inline"
        add field "PostPeriod"
        add field "TaxTotal"
      }
      add layout "InvoiceHeaderRow6" {
        displayName = "InvoiceHeaderRow6"
        layout = "Inline"
        add field "Currency"
        add field "Amount"
      }
      add layout "InvoiceHeaderRow7" {
        displayName = "InvoiceHeaderRow7"
        layout = "Inline"
        add field "CashDiscount"
        add field "Balance"
      }   
    }
  }
}