I have tried to find an online tutorials example of how to use DSS for this group stacking if different filter files, and this one seems pretty close to how I do it:
https://youtu.be/eqf8ZmAd2Mk
Now the guy is not great at explaining things, but have a look at the video about 2:30 in where he talks about ticking the box in the Intermeadiate File tab, this is important as it is the part where you create and save a registered file for each of the ones your grouping.
At the end of the process you pick up the files with the reg extension to take to Photoshop.
It is much quicker to do this than actually explain it.
There used to be a couple of threads on Cloudy Nights which explain it well.