BS19-AM-HH​ Sounds like this is a general Intune question, not specific to macOS, correct? Device Serial Number isn't one of the attributes that can be used for creating a group in Intune. One thing you could do as a workaround is to use Device Category or Group Tags. As you enroll a device, assign a Group Tag based on the Serial Number, then create the group based on the Tag.

Alternatively, you might look at using one of the unused extension attributes in Entra.

Can you please go to our Intune Feedback site to enter that feedback? https://aka.ms/IntuneFeedback. I did find this Feedback that's already been entered, so you can give it an upvote 👍