different frontpage template file ?

Hello!
how do i use 4 different frontpage file like front-1.tpl.php front-2.tpl.php front-3.tpl.php

i'm using this code but it's not working

function _progression_preprocess_page($vars, $hook) {
   switch($hook){
		case 'page':
			if ($vars['is_front']) {
			  $vars['template_file'] = theme_get_setting('frontpage_style');
			}
	} break;
    return $vars;
}

frontpage_style is theme variable in .info file

// get default settings 
function _theme_get_default_settings($theme) {
  $themes = list_themes();

  // Get the default values from the .info file.
  $defaults = !empty($themes[$theme]->info['settings']) ? $themes[$theme]->info['settings'] : array();

  if (!empty($defaults)) {
    // Merge the defaults with the theme settings saved in the database.
    $settings = array_merge($defaults, variable_get('theme_'. $theme .'_settings', array()));
    // Save the settings back to the database.
    variable_set('theme_'. $theme .'_settings', $settings);
    // If the active theme has been loaded, force refresh of Drupal internals.
    if (!empty($GLOBALS['theme_key'])) {
      theme_get_setting('', TRUE);
    }
  }

  // Return the default settings.
  return $defaults;
}