Disconnect previus session if new access-request is received

Hello, Some time ago i've configured a freeeradius file so freeradius could behave in the next way: If an access-request is received and the user (Limited to one simultaneous use) has a previous session with the same mac-address, close the session and validate the user request. I've been searching for this configuration for two days now and i'm not able to find it. Does anyone has this configuration so you can share it with us? Best regards, Juanjo.