Is there a script to remove/hide Department field from new ticket form and default to our default Department?

Is there a script to remove/hide Department field from new ticket form and default to our default Department?

We have two departments that handle tickets. BatchMaster and Product Management.
BatchMaster is the default and the only department where new tickets should be submitted.
Tickets transferred to Product Management should be visible in Help Center but we need to block customers from submitting tickets to it. Is there a script we can use in HC to do this?

Thanks!
Mel