In Dashboard need to turn off notifications/alerts and hide all alerts from certain groups

[Ymca Retirement]

We have a vendor on our wiki and I need to limit all access to what they can see. It looks like the default dashboard has announcements/feeds that allow them to see whatever everyone else is doing. This needs to be turned off. I need to lock down confluence so they only see their space and that's it. They cannot search or look at other content. 

Any ideas how I can do this?