Hide Start new topic button in support forum

[kmk]

Hi all and @Ehren

I am building a section to attend client issue,  after open a thread for the client (I will create a topic then change ownership to that client) I don't need the button "Start New topic" anymore from members side.

So how can I hide the "Start new topic" button of a specific forum? 

The client will use threads created by me (or staff) to communicate with us (staff). 

[Ehren]

I imagine you could just do this with Forum/Group permissions.. Restrict all groups from posting new topics in that forum and then make a group which has permission, and add yourself to that group.