Since the Barriers are driven by the same technology as the decks, it is possible to introduce variables in the templates, and adjust them after placement to create parametric variations. 

For example, if you would like to model a barrier end treatment using a linear transition as shown below:

First you will need to introduce some variables in the barrier template to control the geometry variation, in this case height of the barrier.

After placing the barrier in the model, in the properties panel, select the option to edit the Variable Constraints, and specify the variation for the variable (s) introduced in the template.

 

Resulting Barrier End treatment