Livechat ... default Departments..how to?

Hello
I have 3 Departments(IT, Directors, Office) in my LiveChat. When new user come to my site … he can connect to random department. I need the user to immediately connect to Office…
I tried to use:
w.RocketChat.setDepartment(‘Office’);
in LiveChat code … but its did not help :frowning:
Can you please help ?
Thx