I would think you could edit all the files DSP value and enter:
=If(IsEqual([Channels], 2), Dolby, None)
I didn't know the actual names, so I just used Dolby and None. But hopefully you get the idea.
I just wanted to write a post to the other novices who are just becoming introduced to JRiver.
When trying to modify the properties of a particular track or tracks, in Windows jargon, one would right click and select properties and work from there.
In JRiver, this functionality is called a tag. This is in contrast to something like Google Photos where a tag is typically a list of descriptive labels.
Within Tag, a virtual Pandora's Box opens for every track.
Regarding this specific thread, I can go to Tag, then open the tab for Advanced, then DSP, and then select a preset. The great thing is that you can multiselect tracks and set DSP preset using this Tag/Advanced/DSP workflow.
I still don't know where I can find a list of variables/operators for conditional statements in tag fields.
JRiver is on it's 25th Version. The experts have incredible knowledge and familiarity with the program. Beginners like me, I imagine, have difficulty with the terms and the navigation.
I thank all of you for the forum.