Looking for a script to add one row at the end of a table, merge it and add text

Hi all,

My client decided they want to add a row at the end of all the tables with a note. I figured out how to add the row using the script below, but cannot figure out how to merge that row and then add in the new copy. Currently the tables are one row, three columns. The new row should be merged across all the columns (see example below). Can anyone tell me if this is even possible to script? I have tons of documents I have to do this on so any help would be greatly appreciated!

var curDoc = app.activeDocument;

var allTables = curDoc.stories.everyItem().tables.everyItem().getElements();

for ( var t = 0; t < allTables.length; t++ ) {

    var curTable = allTables;

    var allRows = curTable.rows;

curTable.rows.add(LocationOptions.AT_END);

}