P1 ticket closure restriction

Hi experts ,

 

We are running on Process desginer and in incident workflow when user raise a P1 then only the incident manager should close the incident , however for other priority incidents normal users could close the incident, in the exsiting setup we have the following condition ( user has "Close/Delete" authorization) in the transtion button, we need the add extra condition to restrict only for P1 incidents , kindly suggest how to acheive this.