PAHT Email Subject Line

We have had some comments from our guests that when they have multiple orders with us it is difficult to find the correct ticket email to open.  Has anyone used a dynamic subject line within the PAHT email?  Is that possible?

We'd like to have it describe what's included in the PDF.  For example: "Tickets for Chihuly: In the Forest" where Chihuly: In the Forest is either the perf name or the TNEW title.  

Any thoughts?