Matt,
Assuming that you are using LabVIEW, (or any other programming environment as a matter of fact) you can lump all of your channels into one task and apply the triggering to that one task. All the parameters would be applied to all the channels. For example, in LabVIEW, if you have a task you can just enter multiple channels into the "Physical Channels" control like ai0:8. Once you do that the trigger will be applied to all the channels in the task.
Hope that helps.
Regards,
Raajit L
National Instruments