How to instantiate a new session scope controller on each new tab in liferay 6.2 while keeping the old one

I have come across a Liferay 6.2 based application in which each page is backed by a session scope controller, because of which user is unable to use the same page on two different tabs of browser at the same time. What can be the quickest way to achieve this requirement in Liferay 6.2.

Note: cannot change the scope of the controller to request or view because each page is very detailed and will take a lot of time to revamp.