Mark a Category as Unavailable

Hi there, first off thanks for an amazing plugin.
I am using it to show the availability of artists on a website where each artist is a category in the calendar. What I would like to know is if it is possible to mark an Artist (Category) as unavailable for a certain time. For instance if they are away. I know you can create an event for that category, but getting singers to log into a site is already an accomplishment so I am trying to make this as easy as possible for them.

So basically Arno (link) logs in and sets his category unavailable for 3 days for example and then it shows on the calendar on his page as unavailable for bookings for the long weekend (example).

Thanks again!!
Adrian

The page I need help with: [log in to see the link]