You can package multiple portlets within a common, single, portlet applicatio war file. These portlets can share information through the Application Scope of the PortletSession. Check out my signature links for some free tutorials on the subject.
However, JSR168 portlets don't really call each other. There's no mechanism to do that, and it's not really how portlets are intended to work. Portlets are supposed to be independent creatures sharing space on a portal page.
What you might need is a JSF portlet that allows a wizard like experience through a portlet. It's a very proven pattern.
Also, IBM provides things like C2A, click-2-action, to provide inter-portlet communication. They also provide a PortletService framework to perhaps facilitate sharing information. IBM specific though, so don't bet the interoperabiliy of your portlets on it.
Keep asking questions - we'll get you thinking like a portlet developer in no time!
My req is to show the other features like policy's the user is having other Info about the policy's in seperate portlets after successfull login of the user. Hence I want to call one portlet from the other things to retrive the user related all other Info depending upon successfull login in different portlets. Just want to know the info that there is a login for each and every portlet site is that validated against the user's created in the Application server i.e somthing like IDMS which is having the user details or we can store the info about loginid and password in the database.
The PortalAPI allows you to obtain a User object that allows you to obtain all sorts of information about the user, and the RenderRequest defines a variable called USER_INFO.
Any portlet can grab this information. If the portlets are on the page, you can have them display. The portal page aggregation mechanism will call the view mode of any portlet placed on a page, and perhaps those portlets could grab this information and display the information you're interested in.