Unfortunately, it seems as though this feature isn't currently possible within DirectRT. The only way you could implement this functionality into your experiment would be through the method you've noted. For the most part, there shouldn't be any difference other than a longer and more complex input file.

We will make sure that the next release of DirectRT will have the ability to more easily complete this type of task.

Please let me know if you have any additional questions or if I can help in any way.