using parked domains as codeignitaer controllers

Hi , i have an application built on codeigniter, and there is some controllers like this :

mainsite.com/resellers/controller_a/method_a/input/resellerID

that resellers is directory , controller_a is name of controller and method_a is name of function and input is posted input values, and resellerID is id of reseller,

how i can have this :

mainsite.com/resellers/controller_a/method_a/input/1 equals to otherdomain1.com//controller_a/method_a/input/
mainsite.com/resellers/controller_a/method_a/input/2 equals to otherdomain2.com//controller_a/method_a/input/
mainsite.com/resellers/controller_a/method_a/input/3 equals to otherdomain3.com//controller_a/method_a/input/
....

ressan.ir
CI is nice