session problems

Hi! I have a problem with sessions. I have an application that runs in a browser and on some menu's it window.opens other windows with the same session. let's say that on the main window I have the interface to a tool to do traceroute to a host. In that main window I enter the host to traceroute to and click submit. The form is submitted to another script in a new window with the PHPSESSID in the url because only authenticated users are allowed to use the tool. The secondary window takes the value of the host from the $_POST and runs traceroute and waits for it to finish to display the output. The problem is if I minimize the secondary window and try to go to another menu on the main window before traceroute finishes... I believe that the main script cannot get a lock on the session file and hangs on session_start(). What could I do to make the second script have read-only access to the session file.. not interrupting the activity of the main script. Thanks, Mihai