<!DOCTYPE html>
<html>

  <head>
    <link data-require="bootstrap@3.3.2" data-semver="3.3.2" rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css" />
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/ng-table/0.8.3/ng-table.min.css" />
    <link rel="stylesheet" href="style.css" />
    
    <script data-require="angular.js@1.3.7" data-semver="1.3.7" src="https://code.angularjs.org/1.3.7/angular.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/ng-table/0.8.3/ng-table.min.js"></script>
    <script src="script.js"></script>
  </head>

  <body ng-app="ngTableApp">
    <h1>NgTable filtering array columns</h1>
    <div ng-controller="myFilterController as myCtrl">
      <table ng-table="myCtrl.tableParams" class="table table-condensed table-bordered table-striped table-vmiddle" show-filter="true">
        <tr ng-repeat="item in $data">
          <td data-title="'Name'" sortable="'name'" filter="{'name': 'text'}">{{item.name}}</td>
          <td data-title="'Users'">
            <span style="margin-right: 10px; border: 1px solid black;" ng-repeat="user in item.users">{{user.firstname}} {{user.lastname}}</span>
          </td>
          <td data-title="'Remark'" sortable="'remark'" filter="{'remark': 'text'}">{{item.remark}}</td>
        </tr>
      </table>
    </div>
  </body>

</html>
// Code goes here
var app = angular.module('ngTableApp', ['ngTable'])
  .controller('myFilterController', function($scope, $filter, $q, NgTableParams) {
    var ctrl = this;
    ctrl.data = [{
      name: 'Test A',
      remark: 'test A',
      users: [
        {_id: 1234, firstname: 'A', lastname: 'B'},
        {_id: 2345, firstname: 'B', lastname: 'C'},
        {_id: 3456, firstname: 'C', lastname: 'D'},
        {_id: 4567, firstname: 'D', lastname: 'E'},
      ]
    },
    {
      name: 'Test B',
      remark: 'test B',
      users: [
        {_id: 1234, firstname: 'A', lastname: 'B'},
        {_id: 5678, firstname: 'E', lastname: 'F'},
        {_id: 3456, firstname: 'C', lastname: 'D'},
      ]
    },
    {
      name: 'Test C',
      remark: 'test C',
      users: [
        {_id: 5678, firstname: 'E', lastname: 'F'}
      ]
    }];
    ctrl.tableParams = new NgTableParams({
      page: 1, count: 10,
      sorting: {name: 'asc'}
    },
    {
      data: ctrl.data
    });
  }
)
/* Styles go here */

little plnkr for:
http://stackoverflow.com/questions/42505046/ngtable-filter-column-with-array-data