Page field Custom PHP code conditional logic

[RyanJ]

The admin side gives you the capability to enter your own php code to find selectable pages. Example

return $page->parent->parent;

Are you able to use some conditional checking as well? I have attempted to do so, but with not luck. Example

if ($page->template == "template") {
   return $page->parent;
} else {
   return $page->parent->child;

[Soma]

You can do anything but need to return a Page array.