Since our Using E-Mail Merge Codes post, we have heard from several customers that they were interested in the concept but it seemed like too much work to change their current “record” level setup. So here’s what we would recommend. Send your broadcast in 2 batches. The 1st batch to just your Primary contacts, and the 2nd batch to your slowly growing list of secondary contacts whose merge codes you have populated.
Therefore, over time your broadcast will contain more and more recipients without having to change all your contacts at once.