Yes, MediaLab offers a great way to administer multiple DirectRT input files within a single session--especially when you want to randomize or counter balance the DirectRT files that are being administered. Another option is to make batch files in a folder or on the desktop that can launch the DirectRT sessions automatically with the subjects and condition IDs pre-determined. For the latter solution see the DirectRT user's guide for details or online here:
www.empirisoft.com/directrt/help/directrt_running_from_a_command_prompt.htm