Webaction : how to access to all ongoing web sessions ?

Hello,
Is it possible with Webaction to get access to all ongoing web sessions
?

Example :
 
I store the name of a connected user with 
(setf (websession-variable session "name") "Brown")

I want to print print the name of all connected users
(dolist (session *???*)
  (format t "~A" (websession-variable session "name"))
  )

Thank you for possible advise


Jacques