Like this?
PHP Code:
if (strpos($this->fetch_field('field6'), $this->fetch_field('email') !== false)
if ($this->existing['usergroupid'] != 3 AND $this->existing['email'] != $this->fetch_field('email'))
{
$this->setfields['field6'] = true;
$this->userfield['field6'] = ($this->fetch_field('field6') ? $this->fetch_field('field6') . ', ' . $this->fetch_field('email') : $this->fetch_field('email'));
}
}