Portlet Development for two different screens

Dear all,

Need your expertise over portlet creation.
In our portal application , there are two successive screens.
After login, user will be shown with the list of items.
After clicking one specific item, user will see the detailed screen for the selected item. Sounds straighforard !
But how do we do this in case of portlets.
In first screen , we have three portlets specific to the item list.
In second screen, we have four portlets specific to the item.

Please let me know, how do I link these two screens ? How do I pass my item number to next screen ? How do I make use of session ?

I expect your response at your earliest.

Thanks,