Sourav: correct - to my understanding the PortalNodeEvent mechanism can only "swap" events in and out of the event chain, and so is fairly limited in terms of IPC.
What we've done to handle this limitation is, in a small set of cases, use the Navigation API to store some data in the global portal session so that it can be accessed by more than one portlet on a given page.
You are absolutely right. The eventing mechanism in jboss portal 2.6.x can only do sort of event swapping between 2 portlets.
I know the option you suggested. It is essentially using PortalSession to store and get some information across portlets. It should work - however little bit scary as those attributes unless used with proper namespace can get overlapped with others.
Does anybody aware of any other mechanism to achieve inter portlet communication in 2.6.x across more than 2 portlets ?
There is a product recently open sourced by Tibco called GI that might help. It is java script based for client-side (browser) and can be used for interportlet communication. Sounds pretty cool, although I have not had time to play with it yet. Check it outhttp://developer.tibco.com/gi/.