When the user clicks a record in the portal, you want to see that record displayed on another record? If so, use this script from a button inside the portal row:
Go To Related Record [Show only related records; From table: PortalTable; Using layout: "PortalTable" (PortalTable)]
use your table and layout names in place of "portalTable".
This will pull up a found set of all the portal's records and make the record of the row that was clicked the current record.