You will have to go to CPanel -> Mail -> Account level filtering -> Create new filter. Set the rule name to whatever you want, then filter based on "to" "equals" fill in
admins@-------.x10.mx in the box. Set the action to "pipe to a program" fill in /home/tenx23/path/to/your/file.php, in example. You may want to add another action to "discard message" or else the message will also be delivered to the inbox. Finally, if your php file does not start with a hashbang, this is unlikely to work. The hashbang is #!/usr/bin/php -q. So, your file should look like this:
Code:
#!/usr/bin/php -q
<?php
// code starts here like normal
?>
I haven't done this before, so you may need to do some google searching yourself to get all the answers.