Metrics "Group by" function supports only 3 of com.ibm.snx_profiles.base.XXXXXXXX dimensions. My customer uses an extended one. At the moment there is no way to use it and add it to "Group by" filters. It worked well with Cognos earlier.
support extended fields, like "com.ibm.snx_profiles.ext.ams_Zone" including the possibility to use it as "Group by" filter.