Display Logic Possible in Custom End Pages?

We are attempting to design a custom end page that displays variables within the body of the message using the same logic criteria available for the questions. (We've been able to create the dynamic page we would like to display after the form is submitted, but it only works as a part of the survey itself, rather than the end page. If we add variables to the end page template, they will always display their values.)

Are we missing a way to approach this? The criteria we need to use to decide whether to display certain variables would result in too many options for redirecting to specific external urls or to create different custom messages for every possible combination. It would be so helpful to be able to set up the custom message to display variables only if certain conditions are met.

Is there a workaround or a scripting solution we could try?