Attach file already on server to email

I need to send periodic emails to my organization members, attaching a file that resides on the server.  The file to be attached will change, and its name is stored in a database table.  Is there any way I can have the email attach the correct file by storing the path and name in a variable, and using that variable in the Attachments field of the email?  The only way I can get the file attached is to enter the entire path in the Attachments field of the email action, but that would require the CF7 form to be modified every time it needs to attach a different file.

I got it to work with variables, so response is not needed.