Yes you can. Just assign your users to a role, and protect the CMS admin portlet to this role.
You should read the user guide and the reference guide of JBoss Portal for more information.
In JBoss Portal 2.6, there is a fine-grain security mechanism so it's not a everything/nothing type or security anymore.
Thanx for the reply!
As of my understanding..one needs to modify xml file of a portlet for modifying the security constraints..
I am not able to find any such file for the cms admin portlet.can u please help me regarding this?