You can provide dashboard level permissions.
by taking username of country head into any variable then you can set permissions.
or else you can apply column level permissions from RPD. This link http://obieeblog.wordpress.com/2009/01/15/obiee-data-security-column-level-security/ may be helpful for you based upon your requirement.
We were able to achieve column hiding by following the steps. Thank you..
Now we also require to hide the hierarchy in a similar way. Is is possible to achieve?
We get an error in the report when the user has no access to the hierarchy. Any configuration changes required?