Drupal 7: Views PHP filter to select items allocated into two groups, randomly designate group to select

gistfile1.txt

// FILTER: GLOBAL PHP
// SETUP CODE
global $randvalforslides;
$randvalforslides=rand(1,2);
// FILTER CODE ---------------------------------------------
$node = node_load($row->nid);
$fhg = $node->field_homepage_group;
$fhg1=$fhg['und'][0]['value']; 

global $randvalforslides;
if ( $fhg1 != $randvalforslides )  return TRUE; else return FALSE;