auth flow according to attribute value

Hi all I'm new to freeradius, I would like to know if there is a module that basing on some attribute of the radius request execute a module, i.e. I want to alter the execution flow of the authorize section ... This give me the possibiltity to manage some "business logic" through the configuration of radius server... For example I could analize the "nas-port-type" attribute in the request and autheticate users on different database, basing on such parameter.. Best regards Giuseppe Tricarico