I hope to eventually be able to embed a variable reference inside another. For example:
${Recipient Reference::options::"Neighbor",${Recipient Name}}
This will allow the user to choose between a set of static values OR a custom value that was specified earlier. For example, if you set the recipient name to "Tom", you would be able to choose "Tom" as an option along with "Neighbor". Perhaps you could also add a "Custom" option that they could use to provide custom input without having to have previously specified it.
Currently, this type of syntax causes errors.