More than one email acount @gnus

[Diokletian]

Dear Folks,

I'd like to manage more than only one email account 
with my Gnus-Emacs mail-client. 

Have you an idea how I have to modify my .emacs file? 

Thanks in advance,

Best,
-- 
D.

P.S.

A part of my present configuration:

;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; GNUS Mail POP
;;;;;;;;;;;;;;;;;;;;;;;;;;


(setq nnmail-pop-password-required t)
(setq mail-sources '((pop :server "XX.XXX.XXX"
:user "XXXX@XX.XX"
:password "XXXXXX")))



;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; GNUS Mail SMTP
;;;;;;;;;;;;;;;;;;;;;;;;;;

(require 'sendmail)
(setq message-send-mail-function 'smtpmail-send-it)
(setq smtpmail-smtp-service 25)
(setq smtpmail-debug-info t)
(setq smtpmail-default-smtp-server "XXXXXX")