Well I have three departments using the same phone system and the main one has night mode setup to come on at 7 and go off at 6. But the night mode is picking up for the other two departments and they do not want that. Is there anything I can do to fix this problem.

If these departments have their own phone lines, then remove those lines from the night service ring group and/or change the control set for those lines.

Anyway I can setup a different message for each department?

What voicemail system are you using?

Number tenants depends on voice mail system.