Running Outlook 2007, an Expert has assisted me in coding a script which appends a suffix to the recipient's Email address. For details, please see http://www.experts-exchange.com/Programming/Languages/Visual_Basic/Q_28374041.html
This works just as I had hoped, but there is a small, unexpected issue. I have Outlook configured to suspend "sent" messages in the Outbox until a second instance of Send/Receive is executed. Sometimes I need to review an outbound message, before sending it, and this approach allows me to do that. If I open a message in the Outbox, make any changes, and then send it, the script appends a second suffix to the recipient's Email address. If I'm paying attention, of course I will delete the redundant suffix. However, if there's an easy way to adjust the script so that another suffix won't be added, I'd like to know.