Is there a way to take away available times for only part of the day (rather than just selecting the

I'm wandering if there is a way to take away available times for only part of the day (rather than just selecting the whole day as not available?

like for instance you're normal hours are from 9-5, but on one specific day, you are arriving late and so you don't want to accept appointments from 9-12.

thanks,
-Bruce