Multiple sessions open at same time, is it possible?

Hello, I'm quite new to sessions, an am trying to program a script which needs two sessions ... I have a members area which uses 1 session, and when you click on disconnect it closes the session and the user returns to the login page. I also am programming a shopping cart so members can choose what they would like to download that also uses a session. All worked fine untill I realised that because they both use the same session, when I disconnect from the members area it also obviously deletes all elements from the download cart. I would there for need to have two seperate sessions one for the cart, and one for the members area. And sometimes I will need to have them both open. Is this possible ? I've searched google but not found anything interesting, except session_name, but I still don't know how to open two sessions or close one session but not the other, or open a variable in a specific session ... Thanks in advance, Richard