Auto Assign "Non Billable" in workflow

Auto Assign "Non Billable" in workflow

Good day, 

is there a way to auto-assign a ticket in a workflow to "Non-Billable"

We receive a large no of alert tickets from various devices, we have a workflow that auto-assigns the ticket to tech and auto-closes the ticket, since these are only alerts we don't do any billing. is there a way I can auto assign the billing time to non-billable?