Set Priority on new records based on the subject?

Set Priority on new records based on the subject?

I'm using a form to send information from my website into Desk. I need a way to set the priority of a ticket when the subject contains specific text. I've been trying workflows and macros but can't find a place to set conditions.

For example, if the subject is "Account Closure", I want to set the priority to "High".

Thanks
Jeff