hi Tim,
In the following query, I am selecting all CategoryTypes and creating an IEnumerable OF IEnumerable - IGrouping, I think. What I get though is a list of Categorytype with an embedded igrouping of categories which belong to the parent category. You could use similar logic, I think:
var query = from c in _unGroupedCategoryList
orderby c.CategoryTypeName, c.CategoryName
group c.CategoryName by c.CategoryTypeName into cats
select cats;
this.CategoryList = query.ToList();