I assume that each portlet is being deployed in its own WAR file and that the library JARs required by the portlets are in their WEB-INF/lib directory. As you guesses, such JARs cannot be shared between WARs, as that would be against the spec. Here are a couple of solutions:
1) Places you WARs in an EAR and move the library JARs out of WEB-INF/lib and itn othe EAR (but leave the servlet/portlet JAR, if any, in WEB-INF/lib).
2) Move the library JARs out of WEB-INF/lib and place them into server/xxx/lib.
I would go with option #1.
Thank you peterJ
I will try to go with 1st option