Hide pipeline from other users in dashlet

[epurple]

Hi
We have setup a sugarcrm system for a client.
We have defined 2 Roles: managers and consultant.

Our clients would like to make impossible for consultant to view the full pipeline, but only their own
The manager should be able to see all of them of course

Is there a way to prevent consultant to add a dashlet? (which would be the easiest: remove the dashlet and then then cant add one..)
Or how can we make sure they see only their opportunities in the dashlets?

thanks

epurple