Why does the building appear in more that one section
Is this what you want.
If so, why do you not want to report on all units in the building as they would all be relevant to the section.
E.g. If section 1 is dealing with power and Section 2 is dealing with Staff, then the fact that the building and the unit appears under both IS relevant.
Do you need to restructure your report so that you report by building -> Unit -> section ??
If you only want the unit information to appear once, you may need to revisit the SELECT statement in the database to group data and select unit only on the MIN(section)