Hide Posts from other user within Dashboard

I am working on a site where the owner is wanting to allow others to post. However they do not want the regular contributors to be able to see the entries of other users in the dashboard – only the admin should be able to do this.

I have tried looking for a plugin but have not found anything as yet.

I also found this but it doesnt seem to work with their edition of wordpress http://macdiggs.com/2006/09/11/wordpress-how-to-hide-other-users-posts-in-admin-panel/

Can anyone offer any advice? Or know of a developer who may be able to assist for a fee?