Unable to set Project attributes mandatory in AP invoice line based on Distribution Combination

Summary:

We are trying to set Project attributes (project number, Task Number, Expenditure Item Date, Expenditure Type, Expenditure Organization, Contract Number, Funding Source) mandatory in AP invoice line based on Distribution Combination, cost center value '776XXXXX'.

The issue is we are unable to find the correct binding parameter value for Distribution Combination field.

We tried below and it is not working:
#{bindings.DefaultDistCcid.inputValue ne null and bindings.DefaultDistCcid.inputValue.contains('776XXXXX')}

Please share the correct binding parameter for Distribution Combination so that we can write EL expression and set the project attributes mandatory if
#{bindings.<correct Distribution Combination>.inputValue ne null and bindings.correct Distribution Combination>.inputValue.contains('776XXXXX')}