Community refers to the gathering of the Faithful.
If a private Mass was being celebrated for an individual on the day of the week where the Faithful are encouraged to worship together, it should be discouraged. But the celebration of the Eucharist targeting a particular age group or special occasion of worshipers, is perfectly permissible. The Church has a rich history of celebrating such focused liturgies. For instance, annually the Archdiocese hosts the Anniversary Mass on a Sunday afternoon for couples marking the silver and golden anniversary of their marriages. The Archdiocese just celebrated World Mission Sunday with a special afternoon liturgy for the focus group of Catholics wishing to mark this special day.