Can several different sessions coexist?

Hi, I'd like to register a session and create several session variables. In another part of my site, I'd like to register another session again creating session variables. After a bit, I'd like to destroy this second registered session keeping the first intact. Thus far, whenever I issue: session_unset(); session_destroy(); both sessions are obliterated. Is there a method of managing different sessions where I can create additional sessions and destroy them without losing my initial session? Thanks, Don