Hey, currently custom dimension groupings and custom channel groupings can’t be used in segments.
This makes them less useful than they seem. These features are great - but it loses some oomph when you can’t use it to segment sessions. The workaround is of course to recreate the filters in the the segment - but working as someone who is setting up the system for other analysts to use it’s a bit too much to ask them to do it.
Cheers,