Sort Groups & Aggregates in Report

I'm trying to create a report that uses Groups and Aggregates. There are 2 properties grouped together, one is a Repair Type, and the other is an Item that is associated with the Repair Type. The Aggregate is the sum of the quantity of the item. The report gets the right quantities and groups, but when I preview the report, try to place it as a table, or export it, all of the groups and items are completely disorganized. Below is a screenshot of the result I'm getting. I would like it to sort alphabetically by the Repair Type name, and then list off the items associated to it in the next column. However, no matter what sorting options I do, none of them appear to have any affect on the way the Groups are organized. Does anyone know if these groups can be sorted?