When you open a People record in Smart IT, there is no indicator as to which Support Group is the person's default Support Group. The only way to find out this information is to open the People record in ITSM. For those that work primarily in Smart IT, it would be preferable to have this information available in the Smart IT People interface. The Support Groups don't seem to be listed in an particular order either. See below, where I have circled my default Support group.