You can use the automap feature, but that is generally for all channels of a type, like for example, when you want to move all your HDHomeRun channels to Schedules Directory, or all your ATSC channels to XMLTV etc.
If not by group but by device, is it possible to create two iptv devices each pointed to different playlists? And would they then need to be auto merged to list them as if they were one device?
Went ahead with test by creating two devices from an empty.db3. Works beautifully. Been trying off'n'on to get two epg's to work together for months. Starting at the device level is the way to go. Thanks sub for the tip.