Manage Account Rules - Payroll/Subledger Accounting

Client has multiple segments in their Cost Allocation Key Flexfield which are optional and not displayed in Payroll Costing. None of the Segment Labels are selected, causing no values to be populated when payroll/costing is created. There is a need to define a constant value through Account Rules in order to feed into Subledger Accounting.

Example - Intercompany segment

Can this be achieved using a "Segment" Rule Type and "Constant" Value Type? Essentially hardcoding the value for every instance of the segment. Or is it recommended to define it at the payroll level, where those constant values follow the true payroll transactions?