Question on setting voicemail

Hi, i have a few questions on the voicemail setup. I am using freepbx 2.8.1 and asterisk I have three extensions that are in a ring group and i am using sip trunk. How can i set the voicemail such that if the one of the extensions is busy, the incoming call will be direct to the voicemail.

The second question I like to ask is how do i set the voice mail so that after a certain timing, say 4pm, any incoming call will be direct to the ivr which will automatically inform the caller that our line is closed and to ask the caller to call at another date and time. The caller will not need to press any key to access this message.

Really appreciate if some one can help me out with these.