Automate entry in a field

Hi,
I have two tables: “tb_detalles” y “tb_palabras”, united by a third table, “detalles_palabras”. This last table contains two fields: “detalles_id” y “palabras_id”, which are the main key and which are related to the id of each of the respective “tb_detalles” y “tb_palabras”.
With the Datatable editor I can fill a column with multiple words for each record:

detalles_palabras (table)
detalles_id        palabras_id (fields)
12               2
12               7
12               15
17               2

The summary code that I am using is the following:

$.fn.dataTable.Editor( {
    fields: [ 
    {
        label: "Pal. Clave:",
        name: "tb_palabra[].id",
        type: "select2",
        opts: {
            "placeholder": "Select State",
            "multiple": "multiple",
            "allowClear": true
            } 
        },  
    ]
} );

$('#imagen_tbl').DataTable( {
    columns: [
        { data: "tb_palabra", render: "[, ].palabra" }, 
    ]
} );

Data:

Editor::inst( $db, 'tb_detalle' )

    ->join(
        Mjoin::inst( 'tb_palabra' )
        ->link( 'tb_detalle.id', 'palabra_detalle.detalle_id' )
        ->link( 'tb_palabra.id', 'palabra_detalle.palabra_id' )
        ->order( 'palabra asc' )
        ->fields(
            Field::inst( 'id' )
            ->validator( Validate::required() )
            ->options( Options::inst()
                ->table( 'tb_palabra' )
                ->value( 'id' )
                ->label( 'palabra' )
            ),
            Field::inst( 'palabra' )
        )
        ->where( 'palabra_detalle.modo_id', 1 )
    )
)

I want to add a new functionality and I need, that the table: “detalles_palabras” differentiate the data from other tables. For that I added a new field: “modo_id”

(Before)
detalles_palabras (table)
detalles_id      palabras_id (fields)
12              2
12              7
12              15
17               2

(Now)
detalles_palabras (table)
detalles_id     palabras_id     modo_id (fields)
12               2                   1
12               7                   1
12              15                   1
17              2                    1
Data from a second Datatable
12              7                    2
12              15                   2
23              7                    2
Data from a third Datatable
12              15                   3
23              7                    3
23              5                    3

The question is: How can I do that when I add a word from each of the datatables, I automatically insert the data in the field mode_id, with the information of the corresponding table. With the example code, it would be a 1.

Thank you very much and happy year to all.