Loading Controllers not in folder controllers

[eluser]pisio[/eluser]
hi , hi !
How I can load controller "/protected/admin/panel.php" = {A} instead "/applications/controllers/panel.php" = {B} And if there is {B} extends {A} if there is NO {B} to load only {A} controller ?

I tried with {B} file :

include {A} ;
class {B} extends {A} {}


And class {A} extends CI_Controller {}
but its crashed