Hi John and Jeff!
You will only be able to use Freemarker with entities that have an N:1 relationship. You cannot use Freemarker with entities that have 1:N relationships.
The lists in that subdivision blog post example can only display the same list for everyone. You will not be able to display a different list for every user.
In order to workaround this, you will somehow need to get the information into some accessible location on the record you are sending the email to or onto a record that is connected to the recipient's Lead/Contact/Account via a N:1 relationship. This blog post may be helpful: http://blog.clickdimensions.com/2015/09/making-child-record-data-accessible-to-dynamic-content.html
If you have additional questions regarding this, I would recommend that you open a Support Ticket at support.clickdimensions.com.