How can I send template emails to a different recipient (than the record the data is coming from)?

How can I send template emails to a different recipient (than the record the data is coming from)?

Say I make a nifty template email to pull all the data I need from John Doe's contact record in CRM.  I would like this data to be sent to Bill Smith (not John Doe).  So far, I have to manually change the recipient email address before hitting send.  Surely there is a more elegant option (otherwise will get occasional screw-ups).  

I'd appreciate any suggestions.  

- Brian