BI Publisher Show conditional text when no rows returned for a Group

Hi, I am new to Bi Publisher and developing my first rtf template and trying to learn on-the-fly.  So, I have a report that includes four separate groups.  The report looks great when there is data returned for each of the four groups.  However, when (for example) one of the groups does NOT have any rows returned, I would like (for example) the text “n/a” to be displayed on the report for that group.  As the report currents stands, the section of the report is simply blank for the group (with no rows returned). How can I accomplish this?  Thank